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1// -*- C++ -*-
2//===--------------------------- random -----------------------------------===//
3//
4//                     The LLVM Compiler Infrastructure
5//
6// This file is dual licensed under the MIT and the University of Illinois Open
7// Source Licenses. See LICENSE.TXT for details.
8//
9//===----------------------------------------------------------------------===//
10
11#ifndef _LIBCPP_RANDOM
12#define _LIBCPP_RANDOM
13
14/*
15    random synopsis
16
17#include <initializer_list>
18
19namespace std
20{
21
22// Engines
23
24template <class UIntType, UIntType a, UIntType c, UIntType m>
25class linear_congruential_engine
26{
27public:
28    // types
29    typedef UIntType result_type;
30
31    // engine characteristics
32    static constexpr result_type multiplier = a;
33    static constexpr result_type increment = c;
34    static constexpr result_type modulus = m;
35    static constexpr result_type min() { return c == 0u ? 1u: 0u;}
36    static constexpr result_type max() { return m - 1u;}
37    static constexpr result_type default_seed = 1u;
38
39    // constructors and seeding functions
40    explicit linear_congruential_engine(result_type s = default_seed);
41    template<class Sseq> explicit linear_congruential_engine(Sseq& q);
42    void seed(result_type s = default_seed);
43    template<class Sseq> void seed(Sseq& q);
44
45    // generating functions
46    result_type operator()();
47    void discard(unsigned long long z);
48};
49
50template <class UIntType, UIntType a, UIntType c, UIntType m>
51bool
52operator==(const linear_congruential_engine<UIntType, a, c, m>& x,
53           const linear_congruential_engine<UIntType, a, c, m>& y);
54
55template <class UIntType, UIntType a, UIntType c, UIntType m>
56bool
57operator!=(const linear_congruential_engine<UIntType, a, c, m>& x,
58           const linear_congruential_engine<UIntType, a, c, m>& y);
59
60template <class charT, class traits,
61          class UIntType, UIntType a, UIntType c, UIntType m>
62basic_ostream<charT, traits>&
63operator<<(basic_ostream<charT, traits>& os,
64           const linear_congruential_engine<UIntType, a, c, m>& x);
65
66template <class charT, class traits,
67          class UIntType, UIntType a, UIntType c, UIntType m>
68basic_istream<charT, traits>&
69operator>>(basic_istream<charT, traits>& is,
70           linear_congruential_engine<UIntType, a, c, m>& x);
71
72template <class UIntType, size_t w, size_t n, size_t m, size_t r,
73          UIntType a, size_t u, UIntType d, size_t s,
74          UIntType b, size_t t, UIntType c, size_t l, UIntType f>
75class mersenne_twister_engine
76{
77public:
78    // types
79    typedef UIntType result_type;
80
81    // engine characteristics
82    static constexpr size_t word_size = w;
83    static constexpr size_t state_size = n;
84    static constexpr size_t shift_size = m;
85    static constexpr size_t mask_bits = r;
86    static constexpr result_type xor_mask = a;
87    static constexpr size_t tempering_u = u;
88    static constexpr result_type tempering_d = d;
89    static constexpr size_t tempering_s = s;
90    static constexpr result_type tempering_b = b;
91    static constexpr size_t tempering_t = t;
92    static constexpr result_type tempering_c = c;
93    static constexpr size_t tempering_l = l;
94    static constexpr result_type initialization_multiplier = f;
95    static constexpr result_type min () { return 0; }
96    static constexpr result_type max() { return 2^w - 1; }
97    static constexpr result_type default_seed = 5489u;
98
99    // constructors and seeding functions
100    explicit mersenne_twister_engine(result_type value = default_seed);
101    template<class Sseq> explicit mersenne_twister_engine(Sseq& q);
102    void seed(result_type value = default_seed);
103    template<class Sseq> void seed(Sseq& q);
104
105    // generating functions
106    result_type operator()();
107    void discard(unsigned long long z);
108};
109
110template <class UIntType, size_t w, size_t n, size_t m, size_t r,
111          UIntType a, size_t u, UIntType d, size_t s,
112          UIntType b, size_t t, UIntType c, size_t l, UIntType f>
113bool
114operator==(
115    const mersenne_twister_engine<UIntType, w, n, m, r, a, u, d, s, b, t, c, l, f>& x,
116    const mersenne_twister_engine<UIntType, w, n, m, r, a, u, d, s, b, t, c, l, f>& y);
117
118template <class UIntType, size_t w, size_t n, size_t m, size_t r,
119          UIntType a, size_t u, UIntType d, size_t s,
120          UIntType b, size_t t, UIntType c, size_t l, UIntType f>
121bool
122operator!=(
123    const mersenne_twister_engine<UIntType, w, n, m, r, a, u, d, s, b, t, c, l, f>& x,
124    const mersenne_twister_engine<UIntType, w, n, m, r, a, u, d, s, b, t, c, l, f>& y);
125
126template <class charT, class traits,
127          class UIntType, size_t w, size_t n, size_t m, size_t r,
128          UIntType a, size_t u, UIntType d, size_t s,
129          UIntType b, size_t t, UIntType c, size_t l, UIntType f>
130basic_ostream<charT, traits>&
131operator<<(basic_ostream<charT, traits>& os,
132           const mersenne_twister_engine<UIntType, w, n, m, r, a, u, d, s, b, t, c, l, f>& x);
133
134template <class charT, class traits,
135          class UIntType, size_t w, size_t n, size_t m, size_t r,
136          UIntType a, size_t u, UIntType d, size_t s,
137          UIntType b, size_t t, UIntType c, size_t l, UIntType f>
138basic_istream<charT, traits>&
139operator>>(basic_istream<charT, traits>& is,
140           mersenne_twister_engine<UIntType, w, n, m, r, a, u, d, s, b, t, c, l, f>& x);
141
142template<class UIntType, size_t w, size_t s, size_t r>
143class subtract_with_carry_engine
144{
145public:
146    // types
147    typedef UIntType result_type;
148
149    // engine characteristics
150    static constexpr size_t word_size = w;
151    static constexpr size_t short_lag = s;
152    static constexpr size_t long_lag = r;
153    static constexpr result_type min() { return 0; }
154    static constexpr result_type max() { return m-1; }
155    static constexpr result_type default_seed = 19780503u;
156
157    // constructors and seeding functions
158    explicit subtract_with_carry_engine(result_type value = default_seed);
159    template<class Sseq> explicit subtract_with_carry_engine(Sseq& q);
160    void seed(result_type value = default_seed);
161    template<class Sseq> void seed(Sseq& q);
162
163    // generating functions
164    result_type operator()();
165    void discard(unsigned long long z);
166};
167
168template<class UIntType, size_t w, size_t s, size_t r>
169bool
170operator==(
171    const subtract_with_carry_engine<UIntType, w, s, r>& x,
172    const subtract_with_carry_engine<UIntType, w, s, r>& y);
173
174template<class UIntType, size_t w, size_t s, size_t r>
175bool
176operator!=(
177    const subtract_with_carry_engine<UIntType, w, s, r>& x,
178    const subtract_with_carry_engine<UIntType, w, s, r>& y);
179
180template <class charT, class traits,
181          class UIntType, size_t w, size_t s, size_t r>
182basic_ostream<charT, traits>&
183operator<<(basic_ostream<charT, traits>& os,
184           const subtract_with_carry_engine<UIntType, w, s, r>& x);
185
186template <class charT, class traits,
187          class UIntType, size_t w, size_t s, size_t r>
188basic_istream<charT, traits>&
189operator>>(basic_istream<charT, traits>& is,
190           subtract_with_carry_engine<UIntType, w, s, r>& x);
191
192template<class Engine, size_t p, size_t r>
193class discard_block_engine
194{
195public:
196    // types
197    typedef typename Engine::result_type result_type;
198
199    // engine characteristics
200    static constexpr size_t block_size = p;
201    static constexpr size_t used_block = r;
202    static constexpr result_type min() { return Engine::min(); }
203    static constexpr result_type max() { return Engine::max(); }
204
205    // constructors and seeding functions
206    discard_block_engine();
207    explicit discard_block_engine(const Engine& e);
208    explicit discard_block_engine(Engine&& e);
209    explicit discard_block_engine(result_type s);
210    template<class Sseq> explicit discard_block_engine(Sseq& q);
211    void seed();
212    void seed(result_type s);
213    template<class Sseq> void seed(Sseq& q);
214
215    // generating functions
216    result_type operator()();
217    void discard(unsigned long long z);
218
219    // property functions
220    const Engine& base() const noexcept;
221};
222
223template<class Engine, size_t p, size_t r>
224bool
225operator==(
226    const discard_block_engine<Engine, p, r>& x,
227    const discard_block_engine<Engine, p, r>& y);
228
229template<class Engine, size_t p, size_t r>
230bool
231operator!=(
232    const discard_block_engine<Engine, p, r>& x,
233    const discard_block_engine<Engine, p, r>& y);
234
235template <class charT, class traits,
236          class Engine, size_t p, size_t r>
237basic_ostream<charT, traits>&
238operator<<(basic_ostream<charT, traits>& os,
239           const discard_block_engine<Engine, p, r>& x);
240
241template <class charT, class traits,
242          class Engine, size_t p, size_t r>
243basic_istream<charT, traits>&
244operator>>(basic_istream<charT, traits>& is,
245           discard_block_engine<Engine, p, r>& x);
246
247template<class Engine, size_t w, class UIntType>
248class independent_bits_engine
249{
250public:
251    // types
252    typedef UIntType result_type;
253
254    // engine characteristics
255    static constexpr result_type min() { return 0; }
256    static constexpr result_type max() { return 2^w - 1; }
257
258    // constructors and seeding functions
259    independent_bits_engine();
260    explicit independent_bits_engine(const Engine& e);
261    explicit independent_bits_engine(Engine&& e);
262    explicit independent_bits_engine(result_type s);
263    template<class Sseq> explicit independent_bits_engine(Sseq& q);
264    void seed();
265    void seed(result_type s);
266    template<class Sseq> void seed(Sseq& q);
267
268    // generating functions
269    result_type operator()(); void discard(unsigned long long z);
270
271    // property functions
272    const Engine& base() const noexcept;
273};
274
275template<class Engine, size_t w, class UIntType>
276bool
277operator==(
278    const independent_bits_engine<Engine, w, UIntType>& x,
279    const independent_bits_engine<Engine, w, UIntType>& y);
280
281template<class Engine, size_t w, class UIntType>
282bool
283operator!=(
284    const independent_bits_engine<Engine, w, UIntType>& x,
285    const independent_bits_engine<Engine, w, UIntType>& y);
286
287template <class charT, class traits,
288          class Engine, size_t w, class UIntType>
289basic_ostream<charT, traits>&
290operator<<(basic_ostream<charT, traits>& os,
291           const independent_bits_engine<Engine, w, UIntType>& x);
292
293template <class charT, class traits,
294          class Engine, size_t w, class UIntType>
295basic_istream<charT, traits>&
296operator>>(basic_istream<charT, traits>& is,
297           independent_bits_engine<Engine, w, UIntType>& x);
298
299template<class Engine, size_t k>
300class shuffle_order_engine
301{
302public:
303    // types
304    typedef typename Engine::result_type result_type;
305
306    // engine characteristics
307    static constexpr size_t table_size = k;
308    static constexpr result_type min() { return Engine::min; }
309    static constexpr result_type max() { return Engine::max; }
310
311    // constructors and seeding functions
312    shuffle_order_engine();
313    explicit shuffle_order_engine(const Engine& e);
314    explicit shuffle_order_engine(Engine&& e);
315    explicit shuffle_order_engine(result_type s);
316    template<class Sseq> explicit shuffle_order_engine(Sseq& q);
317    void seed();
318    void seed(result_type s);
319    template<class Sseq> void seed(Sseq& q);
320
321    // generating functions
322    result_type operator()();
323    void discard(unsigned long long z);
324
325    // property functions
326    const Engine& base() const noexcept;
327};
328
329template<class Engine, size_t k>
330bool
331operator==(
332    const shuffle_order_engine<Engine, k>& x,
333    const shuffle_order_engine<Engine, k>& y);
334
335template<class Engine, size_t k>
336bool
337operator!=(
338    const shuffle_order_engine<Engine, k>& x,
339    const shuffle_order_engine<Engine, k>& y);
340
341template <class charT, class traits,
342          class Engine, size_t k>
343basic_ostream<charT, traits>&
344operator<<(basic_ostream<charT, traits>& os,
345           const shuffle_order_engine<Engine, k>& x);
346
347template <class charT, class traits,
348          class Engine, size_t k>
349basic_istream<charT, traits>&
350operator>>(basic_istream<charT, traits>& is,
351           shuffle_order_engine<Engine, k>& x);
352
353typedef linear_congruential_engine<uint_fast32_t, 16807, 0, 2147483647>
354                                                                   minstd_rand0;
355typedef linear_congruential_engine<uint_fast32_t, 48271, 0, 2147483647>
356                                                                    minstd_rand;
357typedef mersenne_twister_engine<uint_fast32_t, 32, 624, 397, 31,
358                                0x9908b0df,
359                                11, 0xffffffff,
360                                7,  0x9d2c5680,
361                                15, 0xefc60000,
362                                18, 1812433253>                         mt19937;
363typedef mersenne_twister_engine<uint_fast64_t, 64, 312, 156, 31,
364                                0xb5026f5aa96619e9,
365                                29, 0x5555555555555555,
366                                17, 0x71d67fffeda60000,
367                                37, 0xfff7eee000000000,
368                                43, 6364136223846793005>             mt19937_64;
369typedef subtract_with_carry_engine<uint_fast32_t, 24, 10, 24>     ranlux24_base;
370typedef subtract_with_carry_engine<uint_fast64_t, 48,  5, 12>     ranlux48_base;
371typedef discard_block_engine<ranlux24_base, 223, 23>                   ranlux24;
372typedef discard_block_engine<ranlux48_base, 389, 11>                   ranlux48;
373typedef shuffle_order_engine<minstd_rand0, 256>                         knuth_b;
374typedef minstd_rand                                       default_random_engine;
375
376// Generators
377
378class random_device
379{
380public:
381    // types
382    typedef unsigned int result_type;
383
384    // generator characteristics
385    static constexpr result_type min() { return numeric_limits<result_type>::min(); }
386    static constexpr result_type max() { return numeric_limits<result_type>::max(); }
387
388    // constructors
389    explicit random_device(const string& token = "/dev/urandom");
390
391    // generating functions
392    result_type operator()();
393
394    // property functions
395    double entropy() const noexcept;
396
397    // no copy functions
398    random_device(const random_device& ) = delete;
399    void operator=(const random_device& ) = delete;
400};
401
402// Utilities
403
404class seed_seq
405{
406public:
407    // types
408    typedef uint_least32_t result_type;
409
410    // constructors
411    seed_seq();
412    template<class T>
413        seed_seq(initializer_list<T> il);
414    template<class InputIterator>
415        seed_seq(InputIterator begin, InputIterator end);
416
417    // generating functions
418    template<class RandomAccessIterator>
419        void generate(RandomAccessIterator begin, RandomAccessIterator end);
420
421    // property functions
422    size_t size() const;
423    template<class OutputIterator>
424        void param(OutputIterator dest) const;
425
426    // no copy functions
427    seed_seq(const seed_seq&) = delete;
428    void operator=(const seed_seq& ) = delete;
429};
430
431template<class RealType, size_t bits, class URNG>
432    RealType generate_canonical(URNG& g);
433
434// Distributions
435
436template<class IntType = int>
437class uniform_int_distribution
438{
439public:
440    // types
441    typedef IntType result_type;
442
443    class param_type
444    {
445    public:
446        typedef uniform_int_distribution distribution_type;
447
448        explicit param_type(IntType a = 0,
449                                    IntType b = numeric_limits<IntType>::max());
450
451        result_type a() const;
452        result_type b() const;
453
454        friend bool operator==(const param_type& x, const param_type& y);
455        friend bool operator!=(const param_type& x, const param_type& y);
456    };
457
458    // constructors and reset functions
459    explicit uniform_int_distribution(IntType a = 0,
460                                    IntType b = numeric_limits<IntType>::max());
461    explicit uniform_int_distribution(const param_type& parm);
462    void reset();
463
464    // generating functions
465    template<class URNG> result_type operator()(URNG& g);
466    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
467
468    // property functions
469    result_type a() const;
470    result_type b() const;
471
472    param_type param() const;
473    void param(const param_type& parm);
474
475    result_type min() const;
476    result_type max() const;
477
478    friend bool operator==(const uniform_int_distribution& x,
479                           const uniform_int_distribution& y);
480    friend bool operator!=(const uniform_int_distribution& x,
481                           const uniform_int_distribution& y);
482
483    template <class charT, class traits>
484    friend
485    basic_ostream<charT, traits>&
486    operator<<(basic_ostream<charT, traits>& os,
487               const uniform_int_distribution& x);
488
489    template <class charT, class traits>
490    friend
491    basic_istream<charT, traits>&
492    operator>>(basic_istream<charT, traits>& is,
493               uniform_int_distribution& x);
494};
495
496template<class RealType = double>
497class uniform_real_distribution
498{
499public:
500    // types
501    typedef RealType result_type;
502
503    class param_type
504    {
505    public:
506        typedef uniform_real_distribution distribution_type;
507
508        explicit param_type(RealType a = 0,
509                            RealType b = 1);
510
511        result_type a() const;
512        result_type b() const;
513
514        friend bool operator==(const param_type& x, const param_type& y);
515        friend bool operator!=(const param_type& x, const param_type& y);
516    };
517
518    // constructors and reset functions
519    explicit uniform_real_distribution(RealType a = 0.0, RealType b = 1.0);
520    explicit uniform_real_distribution(const param_type& parm);
521    void reset();
522
523    // generating functions
524    template<class URNG> result_type operator()(URNG& g);
525    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
526
527    // property functions
528    result_type a() const;
529    result_type b() const;
530
531    param_type param() const;
532    void param(const param_type& parm);
533
534    result_type min() const;
535    result_type max() const;
536
537    friend bool operator==(const uniform_real_distribution& x,
538                           const uniform_real_distribution& y);
539    friend bool operator!=(const uniform_real_distribution& x,
540                           const uniform_real_distribution& y);
541
542    template <class charT, class traits>
543    friend
544    basic_ostream<charT, traits>&
545    operator<<(basic_ostream<charT, traits>& os,
546               const uniform_real_distribution& x);
547
548    template <class charT, class traits>
549    friend
550    basic_istream<charT, traits>&
551    operator>>(basic_istream<charT, traits>& is,
552               uniform_real_distribution& x);
553};
554
555class bernoulli_distribution
556{
557public:
558    // types
559    typedef bool result_type;
560
561    class param_type
562    {
563    public:
564        typedef bernoulli_distribution distribution_type;
565
566        explicit param_type(double p = 0.5);
567
568        double p() const;
569
570        friend bool operator==(const param_type& x, const param_type& y);
571        friend bool operator!=(const param_type& x, const param_type& y);
572    };
573
574    // constructors and reset functions
575    explicit bernoulli_distribution(double p = 0.5);
576    explicit bernoulli_distribution(const param_type& parm);
577    void reset();
578
579    // generating functions
580    template<class URNG> result_type operator()(URNG& g);
581    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
582
583    // property functions
584    double p() const;
585
586    param_type param() const;
587    void param(const param_type& parm);
588
589    result_type min() const;
590    result_type max() const;
591
592    friend bool operator==(const bernoulli_distribution& x,
593                           const bernoulli_distribution& y);
594    friend bool operator!=(const bernoulli_distribution& x,
595                           const bernoulli_distribution& y);
596
597    template <class charT, class traits>
598    friend
599    basic_ostream<charT, traits>&
600    operator<<(basic_ostream<charT, traits>& os,
601               const bernoulli_distribution& x);
602
603    template <class charT, class traits>
604    friend
605    basic_istream<charT, traits>&
606    operator>>(basic_istream<charT, traits>& is,
607               bernoulli_distribution& x);
608};
609
610template<class IntType = int>
611class binomial_distribution
612{
613public:
614    // types
615    typedef IntType result_type;
616
617    class param_type
618    {
619    public:
620        typedef binomial_distribution distribution_type;
621
622        explicit param_type(IntType t = 1, double p = 0.5);
623
624        IntType t() const;
625        double p() const;
626
627        friend bool operator==(const param_type& x, const param_type& y);
628        friend bool operator!=(const param_type& x, const param_type& y);
629    };
630
631    // constructors and reset functions
632    explicit binomial_distribution(IntType t = 1, double p = 0.5);
633    explicit binomial_distribution(const param_type& parm);
634    void reset();
635
636    // generating functions
637    template<class URNG> result_type operator()(URNG& g);
638    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
639
640    // property functions
641    IntType t() const;
642    double p() const;
643
644    param_type param() const;
645    void param(const param_type& parm);
646
647    result_type min() const;
648    result_type max() const;
649
650    friend bool operator==(const binomial_distribution& x,
651                           const binomial_distribution& y);
652    friend bool operator!=(const binomial_distribution& x,
653                           const binomial_distribution& y);
654
655    template <class charT, class traits>
656    friend
657    basic_ostream<charT, traits>&
658    operator<<(basic_ostream<charT, traits>& os,
659               const binomial_distribution& x);
660
661    template <class charT, class traits>
662    friend
663    basic_istream<charT, traits>&
664    operator>>(basic_istream<charT, traits>& is,
665               binomial_distribution& x);
666};
667
668template<class IntType = int>
669class geometric_distribution
670{
671public:
672    // types
673    typedef IntType result_type;
674
675    class param_type
676    {
677    public:
678        typedef geometric_distribution distribution_type;
679
680        explicit param_type(double p = 0.5);
681
682        double p() const;
683
684        friend bool operator==(const param_type& x, const param_type& y);
685        friend bool operator!=(const param_type& x, const param_type& y);
686    };
687
688    // constructors and reset functions
689    explicit geometric_distribution(double p = 0.5);
690    explicit geometric_distribution(const param_type& parm);
691    void reset();
692
693    // generating functions
694    template<class URNG> result_type operator()(URNG& g);
695    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
696
697    // property functions
698    double p() const;
699
700    param_type param() const;
701    void param(const param_type& parm);
702
703    result_type min() const;
704    result_type max() const;
705
706    friend bool operator==(const geometric_distribution& x,
707                           const geometric_distribution& y);
708    friend bool operator!=(const geometric_distribution& x,
709                           const geometric_distribution& y);
710
711    template <class charT, class traits>
712    friend
713    basic_ostream<charT, traits>&
714    operator<<(basic_ostream<charT, traits>& os,
715               const geometric_distribution& x);
716
717    template <class charT, class traits>
718    friend
719    basic_istream<charT, traits>&
720    operator>>(basic_istream<charT, traits>& is,
721               geometric_distribution& x);
722};
723
724template<class IntType = int>
725class negative_binomial_distribution
726{
727public:
728    // types
729    typedef IntType result_type;
730
731    class param_type
732    {
733    public:
734        typedef negative_binomial_distribution distribution_type;
735
736        explicit param_type(result_type k = 1, double p = 0.5);
737
738        result_type k() const;
739        double p() const;
740
741        friend bool operator==(const param_type& x, const param_type& y);
742        friend bool operator!=(const param_type& x, const param_type& y);
743    };
744
745    // constructor and reset functions
746    explicit negative_binomial_distribution(result_type k = 1, double p = 0.5);
747    explicit negative_binomial_distribution(const param_type& parm);
748    void reset();
749
750    // generating functions
751    template<class URNG> result_type operator()(URNG& g);
752    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
753
754    // property functions
755    result_type k() const;
756    double p() const;
757
758    param_type param() const;
759    void param(const param_type& parm);
760
761    result_type min() const;
762    result_type max() const;
763
764    friend bool operator==(const negative_binomial_distribution& x,
765                           const negative_binomial_distribution& y);
766    friend bool operator!=(const negative_binomial_distribution& x,
767                           const negative_binomial_distribution& y);
768
769    template <class charT, class traits>
770    friend
771    basic_ostream<charT, traits>&
772    operator<<(basic_ostream<charT, traits>& os,
773               const negative_binomial_distribution& x);
774
775    template <class charT, class traits>
776    friend
777    basic_istream<charT, traits>&
778    operator>>(basic_istream<charT, traits>& is,
779               negative_binomial_distribution& x);
780};
781
782template<class IntType = int>
783class poisson_distribution
784{
785public:
786    // types
787    typedef IntType result_type;
788
789    class param_type
790    {
791    public:
792        typedef poisson_distribution distribution_type;
793
794        explicit param_type(double mean = 1.0);
795
796        double mean() const;
797
798        friend bool operator==(const param_type& x, const param_type& y);
799        friend bool operator!=(const param_type& x, const param_type& y);
800    };
801
802    // constructors and reset functions
803    explicit poisson_distribution(double mean = 1.0);
804    explicit poisson_distribution(const param_type& parm);
805    void reset();
806
807    // generating functions
808    template<class URNG> result_type operator()(URNG& g);
809    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
810
811    // property functions
812    double mean() const;
813
814    param_type param() const;
815    void param(const param_type& parm);
816
817    result_type min() const;
818    result_type max() const;
819
820    friend bool operator==(const poisson_distribution& x,
821                           const poisson_distribution& y);
822    friend bool operator!=(const poisson_distribution& x,
823                           const poisson_distribution& y);
824
825    template <class charT, class traits>
826    friend
827    basic_ostream<charT, traits>&
828    operator<<(basic_ostream<charT, traits>& os,
829               const poisson_distribution& x);
830
831    template <class charT, class traits>
832    friend
833    basic_istream<charT, traits>&
834    operator>>(basic_istream<charT, traits>& is,
835               poisson_distribution& x);
836};
837
838template<class RealType = double>
839class exponential_distribution
840{
841public:
842    // types
843    typedef RealType result_type;
844
845    class param_type
846    {
847    public:
848        typedef exponential_distribution distribution_type;
849
850        explicit param_type(result_type lambda = 1.0);
851
852        result_type lambda() const;
853
854        friend bool operator==(const param_type& x, const param_type& y);
855        friend bool operator!=(const param_type& x, const param_type& y);
856    };
857
858    // constructors and reset functions
859    explicit exponential_distribution(result_type lambda = 1.0);
860    explicit exponential_distribution(const param_type& parm);
861    void reset();
862
863    // generating functions
864    template<class URNG> result_type operator()(URNG& g);
865    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
866
867    // property functions
868    result_type lambda() const;
869
870    param_type param() const;
871    void param(const param_type& parm);
872
873    result_type min() const;
874    result_type max() const;
875
876    friend bool operator==(const exponential_distribution& x,
877                           const exponential_distribution& y);
878    friend bool operator!=(const exponential_distribution& x,
879                           const exponential_distribution& y);
880
881    template <class charT, class traits>
882    friend
883    basic_ostream<charT, traits>&
884    operator<<(basic_ostream<charT, traits>& os,
885               const exponential_distribution& x);
886
887    template <class charT, class traits>
888    friend
889    basic_istream<charT, traits>&
890    operator>>(basic_istream<charT, traits>& is,
891               exponential_distribution& x);
892};
893
894template<class RealType = double>
895class gamma_distribution
896{
897public:
898    // types
899    typedef RealType result_type;
900
901    class param_type
902    {
903    public:
904        typedef gamma_distribution distribution_type;
905
906        explicit param_type(result_type alpha = 1, result_type beta = 1);
907
908        result_type alpha() const;
909        result_type beta() const;
910
911        friend bool operator==(const param_type& x, const param_type& y);
912        friend bool operator!=(const param_type& x, const param_type& y);
913    };
914
915    // constructors and reset functions
916    explicit gamma_distribution(result_type alpha = 1, result_type beta = 1);
917    explicit gamma_distribution(const param_type& parm);
918    void reset();
919
920    // generating functions
921    template<class URNG> result_type operator()(URNG& g);
922    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
923
924    // property functions
925    result_type alpha() const;
926    result_type beta() const;
927
928    param_type param() const;
929    void param(const param_type& parm);
930
931    result_type min() const;
932    result_type max() const;
933
934    friend bool operator==(const gamma_distribution& x,
935                           const gamma_distribution& y);
936    friend bool operator!=(const gamma_distribution& x,
937                           const gamma_distribution& y);
938
939    template <class charT, class traits>
940    friend
941    basic_ostream<charT, traits>&
942    operator<<(basic_ostream<charT, traits>& os,
943               const gamma_distribution& x);
944
945    template <class charT, class traits>
946    friend
947    basic_istream<charT, traits>&
948    operator>>(basic_istream<charT, traits>& is,
949               gamma_distribution& x);
950};
951
952template<class RealType = double>
953class weibull_distribution
954{
955public:
956    // types
957    typedef RealType result_type;
958
959    class param_type
960    {
961    public:
962        typedef weibull_distribution distribution_type;
963
964        explicit param_type(result_type alpha = 1, result_type beta = 1);
965
966        result_type a() const;
967        result_type b() const;
968
969        friend bool operator==(const param_type& x, const param_type& y);
970        friend bool operator!=(const param_type& x, const param_type& y);
971    };
972
973    // constructor and reset functions
974    explicit weibull_distribution(result_type a = 1, result_type b = 1);
975    explicit weibull_distribution(const param_type& parm);
976    void reset();
977
978    // generating functions
979    template<class URNG> result_type operator()(URNG& g);
980    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
981
982    // property functions
983    result_type a() const;
984    result_type b() const;
985
986    param_type param() const;
987    void param(const param_type& parm);
988
989    result_type min() const;
990    result_type max() const;
991
992    friend bool operator==(const weibull_distribution& x,
993                           const weibull_distribution& y);
994    friend bool operator!=(const weibull_distribution& x,
995                           const weibull_distribution& y);
996
997    template <class charT, class traits>
998    friend
999    basic_ostream<charT, traits>&
1000    operator<<(basic_ostream<charT, traits>& os,
1001               const weibull_distribution& x);
1002
1003    template <class charT, class traits>
1004    friend
1005    basic_istream<charT, traits>&
1006    operator>>(basic_istream<charT, traits>& is,
1007               weibull_distribution& x);
1008};
1009
1010template<class RealType = double>
1011class extreme_value_distribution
1012{
1013public:
1014    // types
1015    typedef RealType result_type;
1016
1017    class param_type
1018    {
1019    public:
1020        typedef extreme_value_distribution distribution_type;
1021
1022        explicit param_type(result_type a = 0, result_type b = 1);
1023
1024        result_type a() const;
1025        result_type b() const;
1026
1027        friend bool operator==(const param_type& x, const param_type& y);
1028        friend bool operator!=(const param_type& x, const param_type& y);
1029    };
1030
1031    // constructor and reset functions
1032    explicit extreme_value_distribution(result_type a = 0, result_type b = 1);
1033    explicit extreme_value_distribution(const param_type& parm);
1034    void reset();
1035
1036    // generating functions
1037    template<class URNG> result_type operator()(URNG& g);
1038    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
1039
1040    // property functions
1041    result_type a() const;
1042    result_type b() const;
1043
1044    param_type param() const;
1045    void param(const param_type& parm);
1046
1047    result_type min() const;
1048    result_type max() const;
1049
1050    friend bool operator==(const extreme_value_distribution& x,
1051                           const extreme_value_distribution& y);
1052    friend bool operator!=(const extreme_value_distribution& x,
1053                           const extreme_value_distribution& y);
1054
1055    template <class charT, class traits>
1056    friend
1057    basic_ostream<charT, traits>&
1058    operator<<(basic_ostream<charT, traits>& os,
1059               const extreme_value_distribution& x);
1060
1061    template <class charT, class traits>
1062    friend
1063    basic_istream<charT, traits>&
1064    operator>>(basic_istream<charT, traits>& is,
1065               extreme_value_distribution& x);
1066};
1067
1068template<class RealType = double>
1069class normal_distribution
1070{
1071public:
1072    // types
1073    typedef RealType result_type;
1074
1075    class param_type
1076    {
1077    public:
1078        typedef normal_distribution distribution_type;
1079
1080        explicit param_type(result_type mean = 0, result_type stddev = 1);
1081
1082        result_type mean() const;
1083        result_type stddev() const;
1084
1085        friend bool operator==(const param_type& x, const param_type& y);
1086        friend bool operator!=(const param_type& x, const param_type& y);
1087    };
1088
1089    // constructors and reset functions
1090    explicit normal_distribution(result_type mean = 0, result_type stddev = 1);
1091    explicit normal_distribution(const param_type& parm);
1092    void reset();
1093
1094    // generating functions
1095    template<class URNG> result_type operator()(URNG& g);
1096    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
1097
1098    // property functions
1099    result_type mean() const;
1100    result_type stddev() const;
1101
1102    param_type param() const;
1103    void param(const param_type& parm);
1104
1105    result_type min() const;
1106    result_type max() const;
1107
1108    friend bool operator==(const normal_distribution& x,
1109                           const normal_distribution& y);
1110    friend bool operator!=(const normal_distribution& x,
1111                           const normal_distribution& y);
1112
1113    template <class charT, class traits>
1114    friend
1115    basic_ostream<charT, traits>&
1116    operator<<(basic_ostream<charT, traits>& os,
1117               const normal_distribution& x);
1118
1119    template <class charT, class traits>
1120    friend
1121    basic_istream<charT, traits>&
1122    operator>>(basic_istream<charT, traits>& is,
1123               normal_distribution& x);
1124};
1125
1126template<class RealType = double>
1127class lognormal_distribution
1128{
1129public:
1130    // types
1131    typedef RealType result_type;
1132
1133    class param_type
1134    {
1135    public:
1136        typedef lognormal_distribution distribution_type;
1137
1138        explicit param_type(result_type m = 0, result_type s = 1);
1139
1140        result_type m() const;
1141        result_type s() const;
1142
1143        friend bool operator==(const param_type& x, const param_type& y);
1144        friend bool operator!=(const param_type& x, const param_type& y);
1145    };
1146
1147    // constructor and reset functions
1148    explicit lognormal_distribution(result_type m = 0, result_type s = 1);
1149    explicit lognormal_distribution(const param_type& parm);
1150    void reset();
1151
1152    // generating functions
1153    template<class URNG> result_type operator()(URNG& g);
1154    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
1155
1156    // property functions
1157    result_type m() const;
1158    result_type s() const;
1159
1160    param_type param() const;
1161    void param(const param_type& parm);
1162
1163    result_type min() const;
1164    result_type max() const;
1165
1166    friend bool operator==(const lognormal_distribution& x,
1167                           const lognormal_distribution& y);
1168    friend bool operator!=(const lognormal_distribution& x,
1169                           const lognormal_distribution& y);
1170
1171    template <class charT, class traits>
1172    friend
1173    basic_ostream<charT, traits>&
1174    operator<<(basic_ostream<charT, traits>& os,
1175               const lognormal_distribution& x);
1176
1177    template <class charT, class traits>
1178    friend
1179    basic_istream<charT, traits>&
1180    operator>>(basic_istream<charT, traits>& is,
1181               lognormal_distribution& x);
1182};
1183
1184template<class RealType = double>
1185class chi_squared_distribution
1186{
1187public:
1188    // types
1189    typedef RealType result_type;
1190
1191    class param_type
1192    {
1193    public:
1194        typedef chi_squared_distribution distribution_type;
1195
1196        explicit param_type(result_type n = 1);
1197
1198        result_type n() const;
1199
1200        friend bool operator==(const param_type& x, const param_type& y);
1201        friend bool operator!=(const param_type& x, const param_type& y);
1202    };
1203
1204    // constructor and reset functions
1205    explicit chi_squared_distribution(result_type n = 1);
1206    explicit chi_squared_distribution(const param_type& parm);
1207    void reset();
1208
1209    // generating functions
1210    template<class URNG> result_type operator()(URNG& g);
1211    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
1212
1213    // property functions
1214    result_type n() const;
1215
1216    param_type param() const;
1217    void param(const param_type& parm);
1218
1219    result_type min() const;
1220    result_type max() const;
1221
1222    friend bool operator==(const chi_squared_distribution& x,
1223                           const chi_squared_distribution& y);
1224    friend bool operator!=(const chi_squared_distribution& x,
1225                           const chi_squared_distribution& y);
1226
1227    template <class charT, class traits>
1228    friend
1229    basic_ostream<charT, traits>&
1230    operator<<(basic_ostream<charT, traits>& os,
1231               const chi_squared_distribution& x);
1232
1233    template <class charT, class traits>
1234    friend
1235    basic_istream<charT, traits>&
1236    operator>>(basic_istream<charT, traits>& is,
1237               chi_squared_distribution& x);
1238};
1239
1240template<class RealType = double>
1241class cauchy_distribution
1242{
1243public:
1244    // types
1245    typedef RealType result_type;
1246
1247    class param_type
1248    {
1249    public:
1250        typedef cauchy_distribution distribution_type;
1251
1252        explicit param_type(result_type a = 0, result_type b = 1);
1253
1254        result_type a() const;
1255        result_type b() const;
1256
1257        friend bool operator==(const param_type& x, const param_type& y);
1258        friend bool operator!=(const param_type& x, const param_type& y);
1259    };
1260
1261    // constructor and reset functions
1262    explicit cauchy_distribution(result_type a = 0, result_type b = 1);
1263    explicit cauchy_distribution(const param_type& parm);
1264    void reset();
1265
1266    // generating functions
1267    template<class URNG> result_type operator()(URNG& g);
1268    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
1269
1270    // property functions
1271    result_type a() const;
1272    result_type b() const;
1273
1274    param_type param() const;
1275    void param(const param_type& parm);
1276
1277    result_type min() const;
1278    result_type max() const;
1279
1280    friend bool operator==(const cauchy_distribution& x,
1281                           const cauchy_distribution& y);
1282    friend bool operator!=(const cauchy_distribution& x,
1283                           const cauchy_distribution& y);
1284
1285    template <class charT, class traits>
1286    friend
1287    basic_ostream<charT, traits>&
1288    operator<<(basic_ostream<charT, traits>& os,
1289               const cauchy_distribution& x);
1290
1291    template <class charT, class traits>
1292    friend
1293    basic_istream<charT, traits>&
1294    operator>>(basic_istream<charT, traits>& is,
1295               cauchy_distribution& x);
1296};
1297
1298template<class RealType = double>
1299class fisher_f_distribution
1300{
1301public:
1302    // types
1303    typedef RealType result_type;
1304
1305    class param_type
1306    {
1307    public:
1308        typedef fisher_f_distribution distribution_type;
1309
1310        explicit param_type(result_type m = 1, result_type n = 1);
1311
1312        result_type m() const;
1313        result_type n() const;
1314
1315        friend bool operator==(const param_type& x, const param_type& y);
1316        friend bool operator!=(const param_type& x, const param_type& y);
1317    };
1318
1319    // constructor and reset functions
1320    explicit fisher_f_distribution(result_type m = 1, result_type n = 1);
1321    explicit fisher_f_distribution(const param_type& parm);
1322    void reset();
1323
1324    // generating functions
1325    template<class URNG> result_type operator()(URNG& g);
1326    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
1327
1328    // property functions
1329    result_type m() const;
1330    result_type n() const;
1331
1332    param_type param() const;
1333    void param(const param_type& parm);
1334
1335    result_type min() const;
1336    result_type max() const;
1337
1338    friend bool operator==(const fisher_f_distribution& x,
1339                           const fisher_f_distribution& y);
1340    friend bool operator!=(const fisher_f_distribution& x,
1341                           const fisher_f_distribution& y);
1342
1343    template <class charT, class traits>
1344    friend
1345    basic_ostream<charT, traits>&
1346    operator<<(basic_ostream<charT, traits>& os,
1347               const fisher_f_distribution& x);
1348
1349    template <class charT, class traits>
1350    friend
1351    basic_istream<charT, traits>&
1352    operator>>(basic_istream<charT, traits>& is,
1353               fisher_f_distribution& x);
1354};
1355
1356template<class RealType = double>
1357class student_t_distribution
1358{
1359public:
1360    // types
1361    typedef RealType result_type;
1362
1363    class param_type
1364    {
1365    public:
1366        typedef student_t_distribution distribution_type;
1367
1368        explicit param_type(result_type n = 1);
1369
1370        result_type n() const;
1371
1372        friend bool operator==(const param_type& x, const param_type& y);
1373        friend bool operator!=(const param_type& x, const param_type& y);
1374    };
1375
1376    // constructor and reset functions
1377    explicit student_t_distribution(result_type n = 1);
1378    explicit student_t_distribution(const param_type& parm);
1379    void reset();
1380
1381    // generating functions
1382    template<class URNG> result_type operator()(URNG& g);
1383    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
1384
1385    // property functions
1386    result_type n() const;
1387
1388    param_type param() const;
1389    void param(const param_type& parm);
1390
1391    result_type min() const;
1392    result_type max() const;
1393
1394    friend bool operator==(const student_t_distribution& x,
1395                           const student_t_distribution& y);
1396    friend bool operator!=(const student_t_distribution& x,
1397                           const student_t_distribution& y);
1398
1399    template <class charT, class traits>
1400    friend
1401    basic_ostream<charT, traits>&
1402    operator<<(basic_ostream<charT, traits>& os,
1403               const student_t_distribution& x);
1404
1405    template <class charT, class traits>
1406    friend
1407    basic_istream<charT, traits>&
1408    operator>>(basic_istream<charT, traits>& is,
1409               student_t_distribution& x);
1410};
1411
1412template<class IntType = int>
1413class discrete_distribution
1414{
1415public:
1416    // types
1417    typedef IntType result_type;
1418
1419    class param_type
1420    {
1421    public:
1422        typedef discrete_distribution distribution_type;
1423
1424        param_type();
1425        template<class InputIterator>
1426            param_type(InputIterator firstW, InputIterator lastW);
1427        param_type(initializer_list<double> wl);
1428        template<class UnaryOperation>
1429            param_type(size_t nw, double xmin, double xmax, UnaryOperation fw);
1430
1431        vector<double> probabilities() const;
1432
1433        friend bool operator==(const param_type& x, const param_type& y);
1434        friend bool operator!=(const param_type& x, const param_type& y);
1435    };
1436
1437    // constructor and reset functions
1438    discrete_distribution();
1439    template<class InputIterator>
1440        discrete_distribution(InputIterator firstW, InputIterator lastW);
1441    discrete_distribution(initializer_list<double> wl);
1442    template<class UnaryOperation>
1443        discrete_distribution(size_t nw, double xmin, double xmax,
1444                              UnaryOperation fw);
1445    explicit discrete_distribution(const param_type& parm);
1446    void reset();
1447
1448    // generating functions
1449    template<class URNG> result_type operator()(URNG& g);
1450    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
1451
1452    // property functions
1453    vector<double> probabilities() const;
1454
1455    param_type param() const;
1456    void param(const param_type& parm);
1457
1458    result_type min() const;
1459    result_type max() const;
1460
1461    friend bool operator==(const discrete_distribution& x,
1462                           const discrete_distribution& y);
1463    friend bool operator!=(const discrete_distribution& x,
1464                           const discrete_distribution& y);
1465
1466    template <class charT, class traits>
1467    friend
1468    basic_ostream<charT, traits>&
1469    operator<<(basic_ostream<charT, traits>& os,
1470               const discrete_distribution& x);
1471
1472    template <class charT, class traits>
1473    friend
1474    basic_istream<charT, traits>&
1475    operator>>(basic_istream<charT, traits>& is,
1476               discrete_distribution& x);
1477};
1478
1479template<class RealType = double>
1480class piecewise_constant_distribution
1481{
1482    // types
1483    typedef RealType result_type;
1484
1485    class param_type
1486    {
1487    public:
1488        typedef piecewise_constant_distribution distribution_type;
1489
1490        param_type();
1491        template<class InputIteratorB, class InputIteratorW>
1492            param_type(InputIteratorB firstB, InputIteratorB lastB,
1493                       InputIteratorW firstW);
1494        template<class UnaryOperation>
1495            param_type(initializer_list<result_type> bl, UnaryOperation fw);
1496        template<class UnaryOperation>
1497            param_type(size_t nw, result_type xmin, result_type xmax,
1498                       UnaryOperation fw);
1499
1500        vector<result_type> intervals() const;
1501        vector<result_type> densities() const;
1502
1503        friend bool operator==(const param_type& x, const param_type& y);
1504        friend bool operator!=(const param_type& x, const param_type& y);
1505    };
1506
1507    // constructor and reset functions
1508    piecewise_constant_distribution();
1509    template<class InputIteratorB, class InputIteratorW>
1510        piecewise_constant_distribution(InputIteratorB firstB,
1511                                        InputIteratorB lastB,
1512                                        InputIteratorW firstW);
1513    template<class UnaryOperation>
1514        piecewise_constant_distribution(initializer_list<result_type> bl,
1515                                        UnaryOperation fw);
1516    template<class UnaryOperation>
1517        piecewise_constant_distribution(size_t nw, result_type xmin,
1518                                        result_type xmax, UnaryOperation fw);
1519    explicit piecewise_constant_distribution(const param_type& parm);
1520    void reset();
1521
1522    // generating functions
1523    template<class URNG> result_type operator()(URNG& g);
1524    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
1525
1526    // property functions
1527    vector<result_type> intervals() const;
1528    vector<result_type> densities() const;
1529
1530    param_type param() const;
1531    void param(const param_type& parm);
1532
1533    result_type min() const;
1534    result_type max() const;
1535
1536    friend bool operator==(const piecewise_constant_distribution& x,
1537                           const piecewise_constant_distribution& y);
1538    friend bool operator!=(const piecewise_constant_distribution& x,
1539                           const piecewise_constant_distribution& y);
1540
1541    template <class charT, class traits>
1542    friend
1543    basic_ostream<charT, traits>&
1544    operator<<(basic_ostream<charT, traits>& os,
1545               const piecewise_constant_distribution& x);
1546
1547    template <class charT, class traits>
1548    friend
1549    basic_istream<charT, traits>&
1550    operator>>(basic_istream<charT, traits>& is,
1551               piecewise_constant_distribution& x);
1552};
1553
1554template<class RealType = double>
1555class piecewise_linear_distribution
1556{
1557    // types
1558    typedef RealType result_type;
1559
1560    class param_type
1561    {
1562    public:
1563        typedef piecewise_linear_distribution distribution_type;
1564
1565        param_type();
1566        template<class InputIteratorB, class InputIteratorW>
1567            param_type(InputIteratorB firstB, InputIteratorB lastB,
1568                       InputIteratorW firstW);
1569        template<class UnaryOperation>
1570            param_type(initializer_list<result_type> bl, UnaryOperation fw);
1571        template<class UnaryOperation>
1572            param_type(size_t nw, result_type xmin, result_type xmax,
1573                       UnaryOperation fw);
1574
1575        vector<result_type> intervals() const;
1576        vector<result_type> densities() const;
1577
1578        friend bool operator==(const param_type& x, const param_type& y);
1579        friend bool operator!=(const param_type& x, const param_type& y);
1580    };
1581
1582    // constructor and reset functions
1583    piecewise_linear_distribution();
1584    template<class InputIteratorB, class InputIteratorW>
1585        piecewise_linear_distribution(InputIteratorB firstB,
1586                                      InputIteratorB lastB,
1587                                      InputIteratorW firstW);
1588
1589    template<class UnaryOperation>
1590        piecewise_linear_distribution(initializer_list<result_type> bl,
1591                                      UnaryOperation fw);
1592
1593    template<class UnaryOperation>
1594        piecewise_linear_distribution(size_t nw, result_type xmin,
1595                                      result_type xmax, UnaryOperation fw);
1596
1597    explicit piecewise_linear_distribution(const param_type& parm);
1598    void reset();
1599
1600    // generating functions
1601    template<class URNG> result_type operator()(URNG& g);
1602    template<class URNG> result_type operator()(URNG& g, const param_type& parm);
1603
1604    // property functions
1605    vector<result_type> intervals() const;
1606    vector<result_type> densities() const;
1607
1608    param_type param() const;
1609    void param(const param_type& parm);
1610
1611    result_type min() const;
1612    result_type max() const;
1613
1614    friend bool operator==(const piecewise_linear_distribution& x,
1615                           const piecewise_linear_distribution& y);
1616    friend bool operator!=(const piecewise_linear_distribution& x,
1617                           const piecewise_linear_distribution& y);
1618
1619    template <class charT, class traits>
1620    friend
1621    basic_ostream<charT, traits>&
1622    operator<<(basic_ostream<charT, traits>& os,
1623               const piecewise_linear_distribution& x);
1624
1625    template <class charT, class traits>
1626    friend
1627    basic_istream<charT, traits>&
1628    operator>>(basic_istream<charT, traits>& is,
1629               piecewise_linear_distribution& x);
1630};
1631
1632} // std
1633*/
1634
1635#include <__config>
1636#include <cstddef>
1637#include <cstdint>
1638#include <cmath>
1639#include <type_traits>
1640#include <initializer_list>
1641#include <limits>
1642#include <algorithm>
1643#include <numeric>
1644#include <vector>
1645#include <string>
1646#include <istream>
1647#include <ostream>
1648
1649#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
1650#pragma GCC system_header
1651#endif
1652
1653_LIBCPP_PUSH_MACROS
1654#include <__undef_macros>
1655
1656
1657_LIBCPP_BEGIN_NAMESPACE_STD
1658
1659// __is_seed_sequence
1660
1661template <class _Sseq, class _Engine>
1662struct __is_seed_sequence
1663{
1664    static _LIBCPP_CONSTEXPR const bool value =
1665              !is_convertible<_Sseq, typename _Engine::result_type>::value &&
1666              !is_same<typename remove_cv<_Sseq>::type, _Engine>::value;
1667};
1668
1669// linear_congruential_engine
1670
1671template <unsigned long long __a, unsigned long long __c,
1672          unsigned long long __m, unsigned long long _Mp,
1673          bool _MightOverflow = (__a != 0 && __m != 0 && __m-1 > (_Mp-__c)/__a)>
1674struct __lce_ta;
1675
1676// 64
1677
1678template <unsigned long long __a, unsigned long long __c, unsigned long long __m>
1679struct __lce_ta<__a, __c, __m, (unsigned long long)(~0), true>
1680{
1681    typedef unsigned long long result_type;
1682    _LIBCPP_INLINE_VISIBILITY
1683    static result_type next(result_type __x)
1684    {
1685        // Schrage's algorithm
1686        const result_type __q = __m / __a;
1687        const result_type __r = __m % __a;
1688        const result_type __t0 = __a * (__x % __q);
1689        const result_type __t1 = __r * (__x / __q);
1690        __x = __t0 + (__t0 < __t1) * __m - __t1;
1691        __x += __c - (__x >= __m - __c) * __m;
1692        return __x;
1693    }
1694};
1695
1696template <unsigned long long __a, unsigned long long __m>
1697struct __lce_ta<__a, 0, __m, (unsigned long long)(~0), true>
1698{
1699    typedef unsigned long long result_type;
1700    _LIBCPP_INLINE_VISIBILITY
1701    static result_type next(result_type __x)
1702    {
1703        // Schrage's algorithm
1704        const result_type __q = __m / __a;
1705        const result_type __r = __m % __a;
1706        const result_type __t0 = __a * (__x % __q);
1707        const result_type __t1 = __r * (__x / __q);
1708        __x = __t0 + (__t0 < __t1) * __m - __t1;
1709        return __x;
1710    }
1711};
1712
1713template <unsigned long long __a, unsigned long long __c, unsigned long long __m>
1714struct __lce_ta<__a, __c, __m, (unsigned long long)(~0), false>
1715{
1716    typedef unsigned long long result_type;
1717    _LIBCPP_INLINE_VISIBILITY
1718    static result_type next(result_type __x)
1719    {
1720        return (__a * __x + __c) % __m;
1721    }
1722};
1723
1724template <unsigned long long __a, unsigned long long __c>
1725struct __lce_ta<__a, __c, 0, (unsigned long long)(~0), false>
1726{
1727    typedef unsigned long long result_type;
1728    _LIBCPP_INLINE_VISIBILITY
1729    static result_type next(result_type __x)
1730    {
1731        return __a * __x + __c;
1732    }
1733};
1734
1735// 32
1736
1737template <unsigned long long _Ap, unsigned long long _Cp, unsigned long long _Mp>
1738struct __lce_ta<_Ap, _Cp, _Mp, unsigned(~0), true>
1739{
1740    typedef unsigned result_type;
1741    _LIBCPP_INLINE_VISIBILITY
1742    static result_type next(result_type __x)
1743    {
1744        const result_type __a = static_cast<result_type>(_Ap);
1745        const result_type __c = static_cast<result_type>(_Cp);
1746        const result_type __m = static_cast<result_type>(_Mp);
1747        // Schrage's algorithm
1748        const result_type __q = __m / __a;
1749        const result_type __r = __m % __a;
1750        const result_type __t0 = __a * (__x % __q);
1751        const result_type __t1 = __r * (__x / __q);
1752        __x = __t0 + (__t0 < __t1) * __m - __t1;
1753        __x += __c - (__x >= __m - __c) * __m;
1754        return __x;
1755    }
1756};
1757
1758template <unsigned long long _Ap, unsigned long long _Mp>
1759struct __lce_ta<_Ap, 0, _Mp, unsigned(~0), true>
1760{
1761    typedef unsigned result_type;
1762    _LIBCPP_INLINE_VISIBILITY
1763    static result_type next(result_type __x)
1764    {
1765        const result_type __a = static_cast<result_type>(_Ap);
1766        const result_type __m = static_cast<result_type>(_Mp);
1767        // Schrage's algorithm
1768        const result_type __q = __m / __a;
1769        const result_type __r = __m % __a;
1770        const result_type __t0 = __a * (__x % __q);
1771        const result_type __t1 = __r * (__x / __q);
1772        __x = __t0 + (__t0 < __t1) * __m - __t1;
1773        return __x;
1774    }
1775};
1776
1777template <unsigned long long _Ap, unsigned long long _Cp, unsigned long long _Mp>
1778struct __lce_ta<_Ap, _Cp, _Mp, unsigned(~0), false>
1779{
1780    typedef unsigned result_type;
1781    _LIBCPP_INLINE_VISIBILITY
1782    static result_type next(result_type __x)
1783    {
1784        const result_type __a = static_cast<result_type>(_Ap);
1785        const result_type __c = static_cast<result_type>(_Cp);
1786        const result_type __m = static_cast<result_type>(_Mp);
1787        return (__a * __x + __c) % __m;
1788    }
1789};
1790
1791template <unsigned long long _Ap, unsigned long long _Cp>
1792struct __lce_ta<_Ap, _Cp, 0, unsigned(~0), false>
1793{
1794    typedef unsigned result_type;
1795    _LIBCPP_INLINE_VISIBILITY
1796    static result_type next(result_type __x)
1797    {
1798        const result_type __a = static_cast<result_type>(_Ap);
1799        const result_type __c = static_cast<result_type>(_Cp);
1800        return __a * __x + __c;
1801    }
1802};
1803
1804// 16
1805
1806template <unsigned long long __a, unsigned long long __c, unsigned long long __m, bool __b>
1807struct __lce_ta<__a, __c, __m, (unsigned short)(~0), __b>
1808{
1809    typedef unsigned short result_type;
1810    _LIBCPP_INLINE_VISIBILITY
1811    static result_type next(result_type __x)
1812    {
1813        return static_cast<result_type>(__lce_ta<__a, __c, __m, unsigned(~0)>::next(__x));
1814    }
1815};
1816
1817template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1818class _LIBCPP_TEMPLATE_VIS linear_congruential_engine;
1819
1820template <class _CharT, class _Traits,
1821          class _Up, _Up _Ap, _Up _Cp, _Up _Np>
1822_LIBCPP_INLINE_VISIBILITY
1823basic_ostream<_CharT, _Traits>&
1824operator<<(basic_ostream<_CharT, _Traits>& __os,
1825           const linear_congruential_engine<_Up, _Ap, _Cp, _Np>&);
1826
1827template <class _CharT, class _Traits,
1828          class _Up, _Up _Ap, _Up _Cp, _Up _Np>
1829basic_istream<_CharT, _Traits>&
1830operator>>(basic_istream<_CharT, _Traits>& __is,
1831           linear_congruential_engine<_Up, _Ap, _Cp, _Np>& __x);
1832
1833template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1834class _LIBCPP_TEMPLATE_VIS linear_congruential_engine
1835{
1836public:
1837    // types
1838    typedef _UIntType result_type;
1839
1840private:
1841    result_type __x_;
1842
1843    static _LIBCPP_CONSTEXPR const result_type _Mp = result_type(~0);
1844
1845    static_assert(__m == 0 || __a < __m, "linear_congruential_engine invalid parameters");
1846    static_assert(__m == 0 || __c < __m, "linear_congruential_engine invalid parameters");
1847public:
1848    static _LIBCPP_CONSTEXPR const result_type _Min = __c == 0u ? 1u: 0u;
1849    static _LIBCPP_CONSTEXPR const result_type _Max = __m - 1u;
1850    static_assert(_Min < _Max,           "linear_congruential_engine invalid parameters");
1851
1852    // engine characteristics
1853    static _LIBCPP_CONSTEXPR const result_type multiplier = __a;
1854    static _LIBCPP_CONSTEXPR const result_type increment = __c;
1855    static _LIBCPP_CONSTEXPR const result_type modulus = __m;
1856    _LIBCPP_INLINE_VISIBILITY
1857    static _LIBCPP_CONSTEXPR result_type min() {return _Min;}
1858    _LIBCPP_INLINE_VISIBILITY
1859    static _LIBCPP_CONSTEXPR result_type max() {return _Max;}
1860    static _LIBCPP_CONSTEXPR const result_type default_seed = 1u;
1861
1862    // constructors and seeding functions
1863    _LIBCPP_INLINE_VISIBILITY
1864    explicit linear_congruential_engine(result_type __s = default_seed)
1865        {seed(__s);}
1866    template<class _Sseq>
1867        _LIBCPP_INLINE_VISIBILITY
1868        explicit linear_congruential_engine(_Sseq& __q,
1869        typename enable_if<__is_seed_sequence<_Sseq, linear_congruential_engine>::value>::type* = 0)
1870        {seed(__q);}
1871    _LIBCPP_INLINE_VISIBILITY
1872    void seed(result_type __s = default_seed)
1873        {seed(integral_constant<bool, __m == 0>(),
1874              integral_constant<bool, __c == 0>(), __s);}
1875    template<class _Sseq>
1876        _LIBCPP_INLINE_VISIBILITY
1877        typename enable_if
1878        <
1879            __is_seed_sequence<_Sseq, linear_congruential_engine>::value,
1880            void
1881        >::type
1882        seed(_Sseq& __q)
1883            {__seed(__q, integral_constant<unsigned,
1884                1 + (__m == 0 ? (sizeof(result_type) * __CHAR_BIT__ - 1)/32
1885                             :  (__m > 0x100000000ull))>());}
1886
1887    // generating functions
1888    _LIBCPP_INLINE_VISIBILITY
1889    result_type operator()()
1890        {return __x_ = static_cast<result_type>(__lce_ta<__a, __c, __m, _Mp>::next(__x_));}
1891    _LIBCPP_INLINE_VISIBILITY
1892    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
1893
1894    friend _LIBCPP_INLINE_VISIBILITY
1895    bool operator==(const linear_congruential_engine& __x,
1896                    const linear_congruential_engine& __y)
1897        {return __x.__x_ == __y.__x_;}
1898    friend _LIBCPP_INLINE_VISIBILITY
1899    bool operator!=(const linear_congruential_engine& __x,
1900                    const linear_congruential_engine& __y)
1901        {return !(__x == __y);}
1902
1903private:
1904
1905    _LIBCPP_INLINE_VISIBILITY
1906    void seed(true_type, true_type, result_type __s) {__x_ = __s == 0 ? 1 : __s;}
1907    _LIBCPP_INLINE_VISIBILITY
1908    void seed(true_type, false_type, result_type __s) {__x_ = __s;}
1909    _LIBCPP_INLINE_VISIBILITY
1910    void seed(false_type, true_type, result_type __s) {__x_ = __s % __m == 0 ?
1911                                                                 1 : __s % __m;}
1912    _LIBCPP_INLINE_VISIBILITY
1913    void seed(false_type, false_type, result_type __s) {__x_ = __s % __m;}
1914
1915    template<class _Sseq>
1916        void __seed(_Sseq& __q, integral_constant<unsigned, 1>);
1917    template<class _Sseq>
1918        void __seed(_Sseq& __q, integral_constant<unsigned, 2>);
1919
1920    template <class _CharT, class _Traits,
1921              class _Up, _Up _Ap, _Up _Cp, _Up _Np>
1922    friend
1923    basic_ostream<_CharT, _Traits>&
1924    operator<<(basic_ostream<_CharT, _Traits>& __os,
1925               const linear_congruential_engine<_Up, _Ap, _Cp, _Np>&);
1926
1927    template <class _CharT, class _Traits,
1928              class _Up, _Up _Ap, _Up _Cp, _Up _Np>
1929    friend
1930    basic_istream<_CharT, _Traits>&
1931    operator>>(basic_istream<_CharT, _Traits>& __is,
1932               linear_congruential_engine<_Up, _Ap, _Cp, _Np>& __x);
1933};
1934
1935template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1936    _LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type
1937    linear_congruential_engine<_UIntType, __a, __c, __m>::multiplier;
1938
1939template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1940    _LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type
1941    linear_congruential_engine<_UIntType, __a, __c, __m>::increment;
1942
1943template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1944    _LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type
1945    linear_congruential_engine<_UIntType, __a, __c, __m>::modulus;
1946
1947template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1948    _LIBCPP_CONSTEXPR const typename linear_congruential_engine<_UIntType, __a, __c, __m>::result_type
1949    linear_congruential_engine<_UIntType, __a, __c, __m>::default_seed;
1950
1951template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1952template<class _Sseq>
1953void
1954linear_congruential_engine<_UIntType, __a, __c, __m>::__seed(_Sseq& __q,
1955                                                 integral_constant<unsigned, 1>)
1956{
1957    const unsigned __k = 1;
1958    uint32_t __ar[__k+3];
1959    __q.generate(__ar, __ar + __k + 3);
1960    result_type __s = static_cast<result_type>(__ar[3] % __m);
1961    __x_ = __c == 0 && __s == 0 ? result_type(1) : __s;
1962}
1963
1964template <class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1965template<class _Sseq>
1966void
1967linear_congruential_engine<_UIntType, __a, __c, __m>::__seed(_Sseq& __q,
1968                                                 integral_constant<unsigned, 2>)
1969{
1970    const unsigned __k = 2;
1971    uint32_t __ar[__k+3];
1972    __q.generate(__ar, __ar + __k + 3);
1973    result_type __s = static_cast<result_type>((__ar[3] +
1974                                              ((uint64_t)__ar[4] << 32)) % __m);
1975    __x_ = __c == 0 && __s == 0 ? result_type(1) : __s;
1976}
1977
1978template <class _CharT, class _Traits,
1979          class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1980inline _LIBCPP_INLINE_VISIBILITY
1981basic_ostream<_CharT, _Traits>&
1982operator<<(basic_ostream<_CharT, _Traits>& __os,
1983           const linear_congruential_engine<_UIntType, __a, __c, __m>& __x)
1984{
1985    __save_flags<_CharT, _Traits> __lx(__os);
1986    __os.flags(ios_base::dec | ios_base::left);
1987    __os.fill(__os.widen(' '));
1988    return __os << __x.__x_;
1989}
1990
1991template <class _CharT, class _Traits,
1992          class _UIntType, _UIntType __a, _UIntType __c, _UIntType __m>
1993basic_istream<_CharT, _Traits>&
1994operator>>(basic_istream<_CharT, _Traits>& __is,
1995           linear_congruential_engine<_UIntType, __a, __c, __m>& __x)
1996{
1997    __save_flags<_CharT, _Traits> __lx(__is);
1998    __is.flags(ios_base::dec | ios_base::skipws);
1999    _UIntType __t;
2000    __is >> __t;
2001    if (!__is.fail())
2002        __x.__x_ = __t;
2003    return __is;
2004}
2005
2006typedef linear_congruential_engine<uint_fast32_t, 16807, 0, 2147483647>
2007                                                                   minstd_rand0;
2008typedef linear_congruential_engine<uint_fast32_t, 48271, 0, 2147483647>
2009                                                                    minstd_rand;
2010typedef minstd_rand                                       default_random_engine;
2011// mersenne_twister_engine
2012
2013template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2014          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2015          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2016class _LIBCPP_TEMPLATE_VIS mersenne_twister_engine;
2017
2018template <class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2019          _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
2020          _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
2021bool
2022operator==(const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2023                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
2024           const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2025                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __y);
2026
2027template <class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2028          _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
2029          _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
2030_LIBCPP_INLINE_VISIBILITY
2031bool
2032operator!=(const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2033                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
2034           const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2035                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __y);
2036
2037template <class _CharT, class _Traits,
2038          class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2039          _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
2040          _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
2041basic_ostream<_CharT, _Traits>&
2042operator<<(basic_ostream<_CharT, _Traits>& __os,
2043           const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2044                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x);
2045
2046template <class _CharT, class _Traits,
2047          class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2048          _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
2049          _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
2050basic_istream<_CharT, _Traits>&
2051operator>>(basic_istream<_CharT, _Traits>& __is,
2052           mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2053                                   _Bp, _Tp, _Cp, _Lp, _Fp>& __x);
2054
2055template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2056          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2057          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2058class _LIBCPP_TEMPLATE_VIS mersenne_twister_engine
2059{
2060public:
2061    // types
2062    typedef _UIntType result_type;
2063
2064private:
2065    result_type __x_[__n];
2066    size_t      __i_;
2067
2068    static_assert(  0 <  __m, "mersenne_twister_engine invalid parameters");
2069    static_assert(__m <= __n, "mersenne_twister_engine invalid parameters");
2070    static _LIBCPP_CONSTEXPR const result_type _Dt = numeric_limits<result_type>::digits;
2071    static_assert(__w <= _Dt, "mersenne_twister_engine invalid parameters");
2072    static_assert(  2 <= __w, "mersenne_twister_engine invalid parameters");
2073    static_assert(__r <= __w, "mersenne_twister_engine invalid parameters");
2074    static_assert(__u <= __w, "mersenne_twister_engine invalid parameters");
2075    static_assert(__s <= __w, "mersenne_twister_engine invalid parameters");
2076    static_assert(__t <= __w, "mersenne_twister_engine invalid parameters");
2077    static_assert(__l <= __w, "mersenne_twister_engine invalid parameters");
2078public:
2079    static _LIBCPP_CONSTEXPR const result_type _Min = 0;
2080    static _LIBCPP_CONSTEXPR const result_type _Max = __w == _Dt ? result_type(~0) :
2081                                                      (result_type(1) << __w) - result_type(1);
2082    static_assert(_Min < _Max, "mersenne_twister_engine invalid parameters");
2083    static_assert(__a <= _Max, "mersenne_twister_engine invalid parameters");
2084    static_assert(__b <= _Max, "mersenne_twister_engine invalid parameters");
2085    static_assert(__c <= _Max, "mersenne_twister_engine invalid parameters");
2086    static_assert(__d <= _Max, "mersenne_twister_engine invalid parameters");
2087    static_assert(__f <= _Max, "mersenne_twister_engine invalid parameters");
2088
2089    // engine characteristics
2090    static _LIBCPP_CONSTEXPR const size_t word_size = __w;
2091    static _LIBCPP_CONSTEXPR const size_t state_size = __n;
2092    static _LIBCPP_CONSTEXPR const size_t shift_size = __m;
2093    static _LIBCPP_CONSTEXPR const size_t mask_bits = __r;
2094    static _LIBCPP_CONSTEXPR const result_type xor_mask = __a;
2095    static _LIBCPP_CONSTEXPR const size_t tempering_u = __u;
2096    static _LIBCPP_CONSTEXPR const result_type tempering_d = __d;
2097    static _LIBCPP_CONSTEXPR const size_t tempering_s = __s;
2098    static _LIBCPP_CONSTEXPR const result_type tempering_b = __b;
2099    static _LIBCPP_CONSTEXPR const size_t tempering_t = __t;
2100    static _LIBCPP_CONSTEXPR const result_type tempering_c = __c;
2101    static _LIBCPP_CONSTEXPR const size_t tempering_l = __l;
2102    static _LIBCPP_CONSTEXPR const result_type initialization_multiplier = __f;
2103    _LIBCPP_INLINE_VISIBILITY
2104    static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
2105    _LIBCPP_INLINE_VISIBILITY
2106    static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
2107    static _LIBCPP_CONSTEXPR const result_type default_seed = 5489u;
2108
2109    // constructors and seeding functions
2110    _LIBCPP_INLINE_VISIBILITY
2111    explicit mersenne_twister_engine(result_type __sd = default_seed)
2112        {seed(__sd);}
2113    template<class _Sseq>
2114        _LIBCPP_INLINE_VISIBILITY
2115        explicit mersenne_twister_engine(_Sseq& __q,
2116        typename enable_if<__is_seed_sequence<_Sseq, mersenne_twister_engine>::value>::type* = 0)
2117        {seed(__q);}
2118    void seed(result_type __sd = default_seed);
2119    template<class _Sseq>
2120        _LIBCPP_INLINE_VISIBILITY
2121        typename enable_if
2122        <
2123            __is_seed_sequence<_Sseq, mersenne_twister_engine>::value,
2124            void
2125        >::type
2126        seed(_Sseq& __q)
2127            {__seed(__q, integral_constant<unsigned, 1 + (__w - 1) / 32>());}
2128
2129    // generating functions
2130    result_type operator()();
2131    _LIBCPP_INLINE_VISIBILITY
2132    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
2133
2134    template <class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2135              _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
2136              _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
2137    friend
2138    bool
2139    operator==(const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2140                                             _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
2141               const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2142                                             _Bp, _Tp, _Cp, _Lp, _Fp>& __y);
2143
2144    template <class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2145              _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
2146              _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
2147    friend
2148    bool
2149    operator!=(const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2150                                             _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
2151               const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2152                                             _Bp, _Tp, _Cp, _Lp, _Fp>& __y);
2153
2154    template <class _CharT, class _Traits,
2155              class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2156              _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
2157              _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
2158    friend
2159    basic_ostream<_CharT, _Traits>&
2160    operator<<(basic_ostream<_CharT, _Traits>& __os,
2161               const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2162                                             _Bp, _Tp, _Cp, _Lp, _Fp>& __x);
2163
2164    template <class _CharT, class _Traits,
2165              class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2166              _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
2167              _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
2168    friend
2169    basic_istream<_CharT, _Traits>&
2170    operator>>(basic_istream<_CharT, _Traits>& __is,
2171               mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2172                                       _Bp, _Tp, _Cp, _Lp, _Fp>& __x);
2173private:
2174
2175    template<class _Sseq>
2176        void __seed(_Sseq& __q, integral_constant<unsigned, 1>);
2177    template<class _Sseq>
2178        void __seed(_Sseq& __q, integral_constant<unsigned, 2>);
2179
2180    template <size_t __count>
2181        _LIBCPP_INLINE_VISIBILITY
2182        static
2183        typename enable_if
2184        <
2185            __count < __w,
2186            result_type
2187        >::type
2188        __lshift(result_type __x) {return (__x << __count) & _Max;}
2189
2190    template <size_t __count>
2191        _LIBCPP_INLINE_VISIBILITY
2192        static
2193        typename enable_if
2194        <
2195            (__count >= __w),
2196            result_type
2197        >::type
2198        __lshift(result_type) {return result_type(0);}
2199
2200    template <size_t __count>
2201        _LIBCPP_INLINE_VISIBILITY
2202        static
2203        typename enable_if
2204        <
2205            __count < _Dt,
2206            result_type
2207        >::type
2208        __rshift(result_type __x) {return __x >> __count;}
2209
2210    template <size_t __count>
2211        _LIBCPP_INLINE_VISIBILITY
2212        static
2213        typename enable_if
2214        <
2215            (__count >= _Dt),
2216            result_type
2217        >::type
2218        __rshift(result_type) {return result_type(0);}
2219};
2220
2221template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2222          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2223          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2224    _LIBCPP_CONSTEXPR const size_t
2225    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::word_size;
2226
2227template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2228          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2229          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2230    _LIBCPP_CONSTEXPR const size_t
2231    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::state_size;
2232
2233template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2234          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2235          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2236    _LIBCPP_CONSTEXPR const size_t
2237    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::shift_size;
2238
2239template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2240          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2241          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2242    _LIBCPP_CONSTEXPR const size_t
2243    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::mask_bits;
2244
2245template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2246          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2247          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2248    _LIBCPP_CONSTEXPR const typename mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::result_type
2249    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::xor_mask;
2250
2251template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2252          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2253          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2254    _LIBCPP_CONSTEXPR const size_t
2255    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_u;
2256
2257template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2258          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2259          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2260    _LIBCPP_CONSTEXPR const typename mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::result_type
2261    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_d;
2262
2263template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2264          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2265          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2266    _LIBCPP_CONSTEXPR const size_t
2267    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_s;
2268
2269template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2270          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2271          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2272    _LIBCPP_CONSTEXPR const typename mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::result_type
2273    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_b;
2274
2275template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2276          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2277          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2278    _LIBCPP_CONSTEXPR const size_t
2279    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_t;
2280
2281template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2282          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2283          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2284    _LIBCPP_CONSTEXPR const typename mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::result_type
2285    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_c;
2286
2287template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2288          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2289          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2290    _LIBCPP_CONSTEXPR const size_t
2291    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::tempering_l;
2292
2293template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2294          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2295          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2296    _LIBCPP_CONSTEXPR const typename mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::result_type
2297    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::initialization_multiplier;
2298
2299template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2300          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2301          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2302    _LIBCPP_CONSTEXPR const typename mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::result_type
2303    mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, __t, __c, __l, __f>::default_seed;
2304
2305template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2306          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2307          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2308void
2309mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b,
2310    __t, __c, __l, __f>::seed(result_type __sd)
2311    _LIBCPP_DISABLE_UBSAN_UNSIGNED_INTEGER_CHECK
2312{   // __w >= 2
2313    __x_[0] = __sd & _Max;
2314    for (size_t __i = 1; __i < __n; ++__i)
2315        __x_[__i] = (__f * (__x_[__i-1] ^ __rshift<__w - 2>(__x_[__i-1])) + __i) & _Max;
2316    __i_ = 0;
2317}
2318
2319template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2320          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2321          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2322template<class _Sseq>
2323void
2324mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b,
2325    __t, __c, __l, __f>::__seed(_Sseq& __q, integral_constant<unsigned, 1>)
2326{
2327    const unsigned __k = 1;
2328    uint32_t __ar[__n * __k];
2329    __q.generate(__ar, __ar + __n * __k);
2330    for (size_t __i = 0; __i < __n; ++__i)
2331        __x_[__i] = static_cast<result_type>(__ar[__i] & _Max);
2332    const result_type __mask = __r == _Dt ? result_type(~0) :
2333                                       (result_type(1) << __r) - result_type(1);
2334    __i_ = 0;
2335    if ((__x_[0] & ~__mask) == 0)
2336    {
2337        for (size_t __i = 1; __i < __n; ++__i)
2338            if (__x_[__i] != 0)
2339                return;
2340        __x_[0] = result_type(1) << (__w - 1);
2341    }
2342}
2343
2344template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2345          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2346          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2347template<class _Sseq>
2348void
2349mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b,
2350    __t, __c, __l, __f>::__seed(_Sseq& __q, integral_constant<unsigned, 2>)
2351{
2352    const unsigned __k = 2;
2353    uint32_t __ar[__n * __k];
2354    __q.generate(__ar, __ar + __n * __k);
2355    for (size_t __i = 0; __i < __n; ++__i)
2356        __x_[__i] = static_cast<result_type>(
2357            (__ar[2 * __i] + ((uint64_t)__ar[2 * __i + 1] << 32)) & _Max);
2358    const result_type __mask = __r == _Dt ? result_type(~0) :
2359                                       (result_type(1) << __r) - result_type(1);
2360    __i_ = 0;
2361    if ((__x_[0] & ~__mask) == 0)
2362    {
2363        for (size_t __i = 1; __i < __n; ++__i)
2364            if (__x_[__i] != 0)
2365                return;
2366        __x_[0] = result_type(1) << (__w - 1);
2367    }
2368}
2369
2370template <class _UIntType, size_t __w, size_t __n, size_t __m, size_t __r,
2371          _UIntType __a, size_t __u, _UIntType __d, size_t __s,
2372          _UIntType __b, size_t __t, _UIntType __c, size_t __l, _UIntType __f>
2373_UIntType
2374mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b,
2375    __t, __c, __l, __f>::operator()()
2376{
2377    const size_t __j = (__i_ + 1) % __n;
2378    const result_type __mask = __r == _Dt ? result_type(~0) :
2379                                       (result_type(1) << __r) - result_type(1);
2380    const result_type _Yp = (__x_[__i_] & ~__mask) | (__x_[__j] & __mask);
2381    const size_t __k = (__i_ + __m) % __n;
2382    __x_[__i_] = __x_[__k] ^ __rshift<1>(_Yp) ^ (__a * (_Yp & 1));
2383    result_type __z = __x_[__i_] ^ (__rshift<__u>(__x_[__i_]) & __d);
2384    __i_ = __j;
2385    __z ^= __lshift<__s>(__z) & __b;
2386    __z ^= __lshift<__t>(__z) & __c;
2387    return __z ^ __rshift<__l>(__z);
2388}
2389
2390template <class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2391          _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
2392          _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
2393bool
2394operator==(const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2395                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
2396           const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2397                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __y)
2398{
2399    if (__x.__i_ == __y.__i_)
2400        return _VSTD::equal(__x.__x_, __x.__x_ + _Np, __y.__x_);
2401    if (__x.__i_ == 0 || __y.__i_ == 0)
2402    {
2403        size_t __j = _VSTD::min(_Np - __x.__i_, _Np - __y.__i_);
2404        if (!_VSTD::equal(__x.__x_ + __x.__i_, __x.__x_ + __x.__i_ + __j,
2405                         __y.__x_ + __y.__i_))
2406            return false;
2407        if (__x.__i_ == 0)
2408            return _VSTD::equal(__x.__x_ + __j, __x.__x_ + _Np, __y.__x_);
2409        return _VSTD::equal(__x.__x_, __x.__x_ + (_Np - __j), __y.__x_ + __j);
2410    }
2411    if (__x.__i_ < __y.__i_)
2412    {
2413        size_t __j = _Np - __y.__i_;
2414        if (!_VSTD::equal(__x.__x_ + __x.__i_, __x.__x_ + (__x.__i_ + __j),
2415                         __y.__x_ + __y.__i_))
2416            return false;
2417        if (!_VSTD::equal(__x.__x_ + (__x.__i_ + __j), __x.__x_ + _Np,
2418                         __y.__x_))
2419            return false;
2420        return _VSTD::equal(__x.__x_, __x.__x_ + __x.__i_,
2421                           __y.__x_ + (_Np - (__x.__i_ + __j)));
2422    }
2423    size_t __j = _Np - __x.__i_;
2424    if (!_VSTD::equal(__y.__x_ + __y.__i_, __y.__x_ + (__y.__i_ + __j),
2425                     __x.__x_ + __x.__i_))
2426        return false;
2427    if (!_VSTD::equal(__y.__x_ + (__y.__i_ + __j), __y.__x_ + _Np,
2428                     __x.__x_))
2429        return false;
2430    return _VSTD::equal(__y.__x_, __y.__x_ + __y.__i_,
2431                       __x.__x_ + (_Np - (__y.__i_ + __j)));
2432}
2433
2434template <class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2435          _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
2436          _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
2437inline _LIBCPP_INLINE_VISIBILITY
2438bool
2439operator!=(const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2440                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x,
2441           const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2442                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __y)
2443{
2444    return !(__x == __y);
2445}
2446
2447template <class _CharT, class _Traits,
2448          class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2449          _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
2450          _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
2451basic_ostream<_CharT, _Traits>&
2452operator<<(basic_ostream<_CharT, _Traits>& __os,
2453           const mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2454                                         _Bp, _Tp, _Cp, _Lp, _Fp>& __x)
2455{
2456    __save_flags<_CharT, _Traits> __lx(__os);
2457    __os.flags(ios_base::dec | ios_base::left);
2458    _CharT __sp = __os.widen(' ');
2459    __os.fill(__sp);
2460    __os << __x.__x_[__x.__i_];
2461    for (size_t __j = __x.__i_ + 1; __j < _Np; ++__j)
2462        __os << __sp << __x.__x_[__j];
2463    for (size_t __j = 0; __j < __x.__i_; ++__j)
2464        __os << __sp << __x.__x_[__j];
2465    return __os;
2466}
2467
2468template <class _CharT, class _Traits,
2469          class _UInt, size_t _Wp, size_t _Np, size_t _Mp, size_t _Rp,
2470          _UInt _Ap, size_t _Up, _UInt _Dp, size_t _Sp,
2471          _UInt _Bp, size_t _Tp, _UInt _Cp, size_t _Lp, _UInt _Fp>
2472basic_istream<_CharT, _Traits>&
2473operator>>(basic_istream<_CharT, _Traits>& __is,
2474           mersenne_twister_engine<_UInt, _Wp, _Np, _Mp, _Rp, _Ap, _Up, _Dp, _Sp,
2475                                   _Bp, _Tp, _Cp, _Lp, _Fp>& __x)
2476{
2477    __save_flags<_CharT, _Traits> __lx(__is);
2478    __is.flags(ios_base::dec | ios_base::skipws);
2479    _UInt __t[_Np];
2480    for (size_t __i = 0; __i < _Np; ++__i)
2481        __is >> __t[__i];
2482    if (!__is.fail())
2483    {
2484        for (size_t __i = 0; __i < _Np; ++__i)
2485            __x.__x_[__i] = __t[__i];
2486        __x.__i_ = 0;
2487    }
2488    return __is;
2489}
2490
2491typedef mersenne_twister_engine<uint_fast32_t, 32, 624, 397, 31,
2492                                0x9908b0df, 11, 0xffffffff,
2493                                7,  0x9d2c5680,
2494                                15, 0xefc60000,
2495                                18, 1812433253>                         mt19937;
2496typedef mersenne_twister_engine<uint_fast64_t, 64, 312, 156, 31,
2497                                0xb5026f5aa96619e9ULL, 29, 0x5555555555555555ULL,
2498                                17, 0x71d67fffeda60000ULL,
2499                                37, 0xfff7eee000000000ULL,
2500                                43, 6364136223846793005ULL>          mt19937_64;
2501
2502// subtract_with_carry_engine
2503
2504template<class _UIntType, size_t __w, size_t __s, size_t __r>
2505class _LIBCPP_TEMPLATE_VIS subtract_with_carry_engine;
2506
2507template<class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
2508bool
2509operator==(
2510    const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x,
2511    const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __y);
2512
2513template<class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
2514_LIBCPP_INLINE_VISIBILITY
2515bool
2516operator!=(
2517    const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x,
2518    const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __y);
2519
2520template <class _CharT, class _Traits,
2521          class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
2522basic_ostream<_CharT, _Traits>&
2523operator<<(basic_ostream<_CharT, _Traits>& __os,
2524           const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x);
2525
2526template <class _CharT, class _Traits,
2527          class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
2528basic_istream<_CharT, _Traits>&
2529operator>>(basic_istream<_CharT, _Traits>& __is,
2530           subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x);
2531
2532template<class _UIntType, size_t __w, size_t __s, size_t __r>
2533class _LIBCPP_TEMPLATE_VIS subtract_with_carry_engine
2534{
2535public:
2536    // types
2537    typedef _UIntType result_type;
2538
2539private:
2540    result_type __x_[__r];
2541    result_type  __c_;
2542    size_t      __i_;
2543
2544    static _LIBCPP_CONSTEXPR const result_type _Dt = numeric_limits<result_type>::digits;
2545    static_assert(  0 <  __w, "subtract_with_carry_engine invalid parameters");
2546    static_assert(__w <= _Dt, "subtract_with_carry_engine invalid parameters");
2547    static_assert(  0 <  __s, "subtract_with_carry_engine invalid parameters");
2548    static_assert(__s <  __r, "subtract_with_carry_engine invalid parameters");
2549public:
2550    static _LIBCPP_CONSTEXPR const result_type _Min = 0;
2551    static _LIBCPP_CONSTEXPR const result_type _Max = __w == _Dt ? result_type(~0) :
2552                                                      (result_type(1) << __w) - result_type(1);
2553    static_assert(_Min < _Max, "subtract_with_carry_engine invalid parameters");
2554
2555    // engine characteristics
2556    static _LIBCPP_CONSTEXPR const size_t word_size = __w;
2557    static _LIBCPP_CONSTEXPR const size_t short_lag = __s;
2558    static _LIBCPP_CONSTEXPR const size_t long_lag = __r;
2559    _LIBCPP_INLINE_VISIBILITY
2560    static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
2561    _LIBCPP_INLINE_VISIBILITY
2562    static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
2563    static _LIBCPP_CONSTEXPR const result_type default_seed = 19780503u;
2564
2565    // constructors and seeding functions
2566    _LIBCPP_INLINE_VISIBILITY
2567    explicit subtract_with_carry_engine(result_type __sd = default_seed)
2568        {seed(__sd);}
2569    template<class _Sseq>
2570        _LIBCPP_INLINE_VISIBILITY
2571        explicit subtract_with_carry_engine(_Sseq& __q,
2572        typename enable_if<__is_seed_sequence<_Sseq, subtract_with_carry_engine>::value>::type* = 0)
2573        {seed(__q);}
2574    _LIBCPP_INLINE_VISIBILITY
2575    void seed(result_type __sd = default_seed)
2576        {seed(__sd, integral_constant<unsigned, 1 + (__w - 1) / 32>());}
2577    template<class _Sseq>
2578        _LIBCPP_INLINE_VISIBILITY
2579        typename enable_if
2580        <
2581            __is_seed_sequence<_Sseq, subtract_with_carry_engine>::value,
2582            void
2583        >::type
2584        seed(_Sseq& __q)
2585            {__seed(__q, integral_constant<unsigned, 1 + (__w - 1) / 32>());}
2586
2587    // generating functions
2588    result_type operator()();
2589    _LIBCPP_INLINE_VISIBILITY
2590    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
2591
2592    template<class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
2593    friend
2594    bool
2595    operator==(
2596        const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x,
2597        const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __y);
2598
2599    template<class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
2600    friend
2601    bool
2602    operator!=(
2603        const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x,
2604        const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __y);
2605
2606    template <class _CharT, class _Traits,
2607              class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
2608    friend
2609    basic_ostream<_CharT, _Traits>&
2610    operator<<(basic_ostream<_CharT, _Traits>& __os,
2611               const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x);
2612
2613    template <class _CharT, class _Traits,
2614              class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
2615    friend
2616    basic_istream<_CharT, _Traits>&
2617    operator>>(basic_istream<_CharT, _Traits>& __is,
2618               subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x);
2619
2620private:
2621
2622    void seed(result_type __sd, integral_constant<unsigned, 1>);
2623    void seed(result_type __sd, integral_constant<unsigned, 2>);
2624    template<class _Sseq>
2625        void __seed(_Sseq& __q, integral_constant<unsigned, 1>);
2626    template<class _Sseq>
2627        void __seed(_Sseq& __q, integral_constant<unsigned, 2>);
2628};
2629
2630template<class _UIntType, size_t __w, size_t __s, size_t __r>
2631    _LIBCPP_CONSTEXPR const size_t subtract_with_carry_engine<_UIntType, __w, __s, __r>::word_size;
2632
2633template<class _UIntType, size_t __w, size_t __s, size_t __r>
2634    _LIBCPP_CONSTEXPR const size_t subtract_with_carry_engine<_UIntType, __w, __s, __r>::short_lag;
2635
2636template<class _UIntType, size_t __w, size_t __s, size_t __r>
2637    _LIBCPP_CONSTEXPR const size_t subtract_with_carry_engine<_UIntType, __w, __s, __r>::long_lag;
2638
2639template<class _UIntType, size_t __w, size_t __s, size_t __r>
2640    _LIBCPP_CONSTEXPR const typename subtract_with_carry_engine<_UIntType, __w, __s, __r>::result_type
2641    subtract_with_carry_engine<_UIntType, __w, __s, __r>::default_seed;
2642
2643template<class _UIntType, size_t __w, size_t __s, size_t __r>
2644void
2645subtract_with_carry_engine<_UIntType, __w, __s, __r>::seed(result_type __sd,
2646        integral_constant<unsigned, 1>)
2647{
2648    linear_congruential_engine<result_type, 40014u, 0u, 2147483563u>
2649        __e(__sd == 0u ? default_seed : __sd);
2650    for (size_t __i = 0; __i < __r; ++__i)
2651        __x_[__i] = static_cast<result_type>(__e() & _Max);
2652    __c_ = __x_[__r-1] == 0;
2653    __i_ = 0;
2654}
2655
2656template<class _UIntType, size_t __w, size_t __s, size_t __r>
2657void
2658subtract_with_carry_engine<_UIntType, __w, __s, __r>::seed(result_type __sd,
2659        integral_constant<unsigned, 2>)
2660{
2661    linear_congruential_engine<result_type, 40014u, 0u, 2147483563u>
2662        __e(__sd == 0u ? default_seed : __sd);
2663    for (size_t __i = 0; __i < __r; ++__i)
2664    {
2665        result_type __e0 = __e();
2666        __x_[__i] = static_cast<result_type>(
2667                                    (__e0 + ((uint64_t)__e() << 32)) & _Max);
2668    }
2669    __c_ = __x_[__r-1] == 0;
2670    __i_ = 0;
2671}
2672
2673template<class _UIntType, size_t __w, size_t __s, size_t __r>
2674template<class _Sseq>
2675void
2676subtract_with_carry_engine<_UIntType, __w, __s, __r>::__seed(_Sseq& __q,
2677        integral_constant<unsigned, 1>)
2678{
2679    const unsigned __k = 1;
2680    uint32_t __ar[__r * __k];
2681    __q.generate(__ar, __ar + __r * __k);
2682    for (size_t __i = 0; __i < __r; ++__i)
2683        __x_[__i] = static_cast<result_type>(__ar[__i] & _Max);
2684    __c_ = __x_[__r-1] == 0;
2685    __i_ = 0;
2686}
2687
2688template<class _UIntType, size_t __w, size_t __s, size_t __r>
2689template<class _Sseq>
2690void
2691subtract_with_carry_engine<_UIntType, __w, __s, __r>::__seed(_Sseq& __q,
2692        integral_constant<unsigned, 2>)
2693{
2694    const unsigned __k = 2;
2695    uint32_t __ar[__r * __k];
2696    __q.generate(__ar, __ar + __r * __k);
2697    for (size_t __i = 0; __i < __r; ++__i)
2698        __x_[__i] = static_cast<result_type>(
2699                  (__ar[2 * __i] + ((uint64_t)__ar[2 * __i + 1] << 32)) & _Max);
2700    __c_ = __x_[__r-1] == 0;
2701    __i_ = 0;
2702}
2703
2704template<class _UIntType, size_t __w, size_t __s, size_t __r>
2705_UIntType
2706subtract_with_carry_engine<_UIntType, __w, __s, __r>::operator()()
2707{
2708    const result_type& __xs = __x_[(__i_ + (__r - __s)) % __r];
2709    result_type& __xr = __x_[__i_];
2710    result_type __new_c = __c_ == 0 ? __xs < __xr : __xs != 0 ? __xs <= __xr : 1;
2711    __xr = (__xs - __xr - __c_) & _Max;
2712    __c_ = __new_c;
2713    __i_ = (__i_ + 1) % __r;
2714    return __xr;
2715}
2716
2717template<class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
2718bool
2719operator==(
2720    const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x,
2721    const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __y)
2722{
2723    if (__x.__c_ != __y.__c_)
2724        return false;
2725    if (__x.__i_ == __y.__i_)
2726        return _VSTD::equal(__x.__x_, __x.__x_ + _Rp, __y.__x_);
2727    if (__x.__i_ == 0 || __y.__i_ == 0)
2728    {
2729        size_t __j = _VSTD::min(_Rp - __x.__i_, _Rp - __y.__i_);
2730        if (!_VSTD::equal(__x.__x_ + __x.__i_, __x.__x_ + __x.__i_ + __j,
2731                         __y.__x_ + __y.__i_))
2732            return false;
2733        if (__x.__i_ == 0)
2734            return _VSTD::equal(__x.__x_ + __j, __x.__x_ + _Rp, __y.__x_);
2735        return _VSTD::equal(__x.__x_, __x.__x_ + (_Rp - __j), __y.__x_ + __j);
2736    }
2737    if (__x.__i_ < __y.__i_)
2738    {
2739        size_t __j = _Rp - __y.__i_;
2740        if (!_VSTD::equal(__x.__x_ + __x.__i_, __x.__x_ + (__x.__i_ + __j),
2741                         __y.__x_ + __y.__i_))
2742            return false;
2743        if (!_VSTD::equal(__x.__x_ + (__x.__i_ + __j), __x.__x_ + _Rp,
2744                         __y.__x_))
2745            return false;
2746        return _VSTD::equal(__x.__x_, __x.__x_ + __x.__i_,
2747                           __y.__x_ + (_Rp - (__x.__i_ + __j)));
2748    }
2749    size_t __j = _Rp - __x.__i_;
2750    if (!_VSTD::equal(__y.__x_ + __y.__i_, __y.__x_ + (__y.__i_ + __j),
2751                     __x.__x_ + __x.__i_))
2752        return false;
2753    if (!_VSTD::equal(__y.__x_ + (__y.__i_ + __j), __y.__x_ + _Rp,
2754                     __x.__x_))
2755        return false;
2756    return _VSTD::equal(__y.__x_, __y.__x_ + __y.__i_,
2757                       __x.__x_ + (_Rp - (__y.__i_ + __j)));
2758}
2759
2760template<class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
2761inline _LIBCPP_INLINE_VISIBILITY
2762bool
2763operator!=(
2764    const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x,
2765    const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __y)
2766{
2767    return !(__x == __y);
2768}
2769
2770template <class _CharT, class _Traits,
2771          class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
2772basic_ostream<_CharT, _Traits>&
2773operator<<(basic_ostream<_CharT, _Traits>& __os,
2774           const subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x)
2775{
2776    __save_flags<_CharT, _Traits> __lx(__os);
2777    __os.flags(ios_base::dec | ios_base::left);
2778    _CharT __sp = __os.widen(' ');
2779    __os.fill(__sp);
2780    __os << __x.__x_[__x.__i_];
2781    for (size_t __j = __x.__i_ + 1; __j < _Rp; ++__j)
2782        __os << __sp << __x.__x_[__j];
2783    for (size_t __j = 0; __j < __x.__i_; ++__j)
2784        __os << __sp << __x.__x_[__j];
2785    __os << __sp << __x.__c_;
2786    return __os;
2787}
2788
2789template <class _CharT, class _Traits,
2790          class _UInt, size_t _Wp, size_t _Sp, size_t _Rp>
2791basic_istream<_CharT, _Traits>&
2792operator>>(basic_istream<_CharT, _Traits>& __is,
2793           subtract_with_carry_engine<_UInt, _Wp, _Sp, _Rp>& __x)
2794{
2795    __save_flags<_CharT, _Traits> __lx(__is);
2796    __is.flags(ios_base::dec | ios_base::skipws);
2797    _UInt __t[_Rp+1];
2798    for (size_t __i = 0; __i < _Rp+1; ++__i)
2799        __is >> __t[__i];
2800    if (!__is.fail())
2801    {
2802        for (size_t __i = 0; __i < _Rp; ++__i)
2803            __x.__x_[__i] = __t[__i];
2804        __x.__c_ = __t[_Rp];
2805        __x.__i_ = 0;
2806    }
2807    return __is;
2808}
2809
2810typedef subtract_with_carry_engine<uint_fast32_t, 24, 10, 24>     ranlux24_base;
2811typedef subtract_with_carry_engine<uint_fast64_t, 48,  5, 12>     ranlux48_base;
2812
2813// discard_block_engine
2814
2815template<class _Engine, size_t __p, size_t __r>
2816class _LIBCPP_TEMPLATE_VIS discard_block_engine
2817{
2818    _Engine __e_;
2819    int     __n_;
2820
2821    static_assert(  0 <  __r, "discard_block_engine invalid parameters");
2822    static_assert(__r <= __p, "discard_block_engine invalid parameters");
2823    static_assert(__r <= INT_MAX, "discard_block_engine invalid parameters");
2824public:
2825    // types
2826    typedef typename _Engine::result_type result_type;
2827
2828    // engine characteristics
2829    static _LIBCPP_CONSTEXPR const size_t block_size = __p;
2830    static _LIBCPP_CONSTEXPR const size_t used_block = __r;
2831
2832#ifdef _LIBCPP_CXX03_LANG
2833    static const result_type _Min = _Engine::_Min;
2834    static const result_type _Max = _Engine::_Max;
2835#else
2836    static _LIBCPP_CONSTEXPR const result_type _Min = _Engine::min();
2837    static _LIBCPP_CONSTEXPR const result_type _Max = _Engine::max();
2838#endif
2839
2840    _LIBCPP_INLINE_VISIBILITY
2841    static _LIBCPP_CONSTEXPR result_type min() { return _Engine::min(); }
2842    _LIBCPP_INLINE_VISIBILITY
2843    static _LIBCPP_CONSTEXPR result_type max() { return _Engine::max(); }
2844
2845    // constructors and seeding functions
2846    _LIBCPP_INLINE_VISIBILITY
2847    discard_block_engine() : __n_(0) {}
2848    _LIBCPP_INLINE_VISIBILITY
2849    explicit discard_block_engine(const _Engine& __e)
2850        : __e_(__e), __n_(0) {}
2851#ifndef _LIBCPP_CXX03_LANG
2852    _LIBCPP_INLINE_VISIBILITY
2853    explicit discard_block_engine(_Engine&& __e)
2854        : __e_(_VSTD::move(__e)), __n_(0) {}
2855#endif  // _LIBCPP_CXX03_LANG
2856    _LIBCPP_INLINE_VISIBILITY
2857    explicit discard_block_engine(result_type __sd) : __e_(__sd), __n_(0) {}
2858    template<class _Sseq>
2859        _LIBCPP_INLINE_VISIBILITY
2860        explicit discard_block_engine(_Sseq& __q,
2861        typename enable_if<__is_seed_sequence<_Sseq, discard_block_engine>::value &&
2862                           !is_convertible<_Sseq, _Engine>::value>::type* = 0)
2863        : __e_(__q), __n_(0) {}
2864    _LIBCPP_INLINE_VISIBILITY
2865    void seed() {__e_.seed(); __n_ = 0;}
2866    _LIBCPP_INLINE_VISIBILITY
2867    void seed(result_type __sd) {__e_.seed(__sd); __n_ = 0;}
2868    template<class _Sseq>
2869        _LIBCPP_INLINE_VISIBILITY
2870        typename enable_if
2871        <
2872            __is_seed_sequence<_Sseq, discard_block_engine>::value,
2873            void
2874        >::type
2875        seed(_Sseq& __q) {__e_.seed(__q); __n_ = 0;}
2876
2877    // generating functions
2878    result_type operator()();
2879    _LIBCPP_INLINE_VISIBILITY
2880    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
2881
2882    // property functions
2883    _LIBCPP_INLINE_VISIBILITY
2884    const _Engine& base() const _NOEXCEPT {return __e_;}
2885
2886    template<class _Eng, size_t _Pp, size_t _Rp>
2887    friend
2888    bool
2889    operator==(
2890        const discard_block_engine<_Eng, _Pp, _Rp>& __x,
2891        const discard_block_engine<_Eng, _Pp, _Rp>& __y);
2892
2893    template<class _Eng, size_t _Pp, size_t _Rp>
2894    friend
2895    bool
2896    operator!=(
2897        const discard_block_engine<_Eng, _Pp, _Rp>& __x,
2898        const discard_block_engine<_Eng, _Pp, _Rp>& __y);
2899
2900    template <class _CharT, class _Traits,
2901              class _Eng, size_t _Pp, size_t _Rp>
2902    friend
2903    basic_ostream<_CharT, _Traits>&
2904    operator<<(basic_ostream<_CharT, _Traits>& __os,
2905               const discard_block_engine<_Eng, _Pp, _Rp>& __x);
2906
2907    template <class _CharT, class _Traits,
2908              class _Eng, size_t _Pp, size_t _Rp>
2909    friend
2910    basic_istream<_CharT, _Traits>&
2911    operator>>(basic_istream<_CharT, _Traits>& __is,
2912               discard_block_engine<_Eng, _Pp, _Rp>& __x);
2913};
2914
2915template<class _Engine, size_t __p, size_t __r>
2916    _LIBCPP_CONSTEXPR const size_t discard_block_engine<_Engine, __p, __r>::block_size;
2917
2918template<class _Engine, size_t __p, size_t __r>
2919    _LIBCPP_CONSTEXPR const size_t discard_block_engine<_Engine, __p, __r>::used_block;
2920
2921template<class _Engine, size_t __p, size_t __r>
2922typename discard_block_engine<_Engine, __p, __r>::result_type
2923discard_block_engine<_Engine, __p, __r>::operator()()
2924{
2925    if (__n_ >= static_cast<int>(__r))
2926    {
2927        __e_.discard(__p - __r);
2928        __n_ = 0;
2929    }
2930    ++__n_;
2931    return __e_();
2932}
2933
2934template<class _Eng, size_t _Pp, size_t _Rp>
2935inline _LIBCPP_INLINE_VISIBILITY
2936bool
2937operator==(const discard_block_engine<_Eng, _Pp, _Rp>& __x,
2938           const discard_block_engine<_Eng, _Pp, _Rp>& __y)
2939{
2940    return __x.__n_ == __y.__n_ && __x.__e_ == __y.__e_;
2941}
2942
2943template<class _Eng, size_t _Pp, size_t _Rp>
2944inline _LIBCPP_INLINE_VISIBILITY
2945bool
2946operator!=(const discard_block_engine<_Eng, _Pp, _Rp>& __x,
2947           const discard_block_engine<_Eng, _Pp, _Rp>& __y)
2948{
2949    return !(__x == __y);
2950}
2951
2952template <class _CharT, class _Traits,
2953          class _Eng, size_t _Pp, size_t _Rp>
2954basic_ostream<_CharT, _Traits>&
2955operator<<(basic_ostream<_CharT, _Traits>& __os,
2956           const discard_block_engine<_Eng, _Pp, _Rp>& __x)
2957{
2958    __save_flags<_CharT, _Traits> __lx(__os);
2959    __os.flags(ios_base::dec | ios_base::left);
2960    _CharT __sp = __os.widen(' ');
2961    __os.fill(__sp);
2962    return __os << __x.__e_ << __sp << __x.__n_;
2963}
2964
2965template <class _CharT, class _Traits,
2966          class _Eng, size_t _Pp, size_t _Rp>
2967basic_istream<_CharT, _Traits>&
2968operator>>(basic_istream<_CharT, _Traits>& __is,
2969           discard_block_engine<_Eng, _Pp, _Rp>& __x)
2970{
2971    __save_flags<_CharT, _Traits> __lx(__is);
2972    __is.flags(ios_base::dec | ios_base::skipws);
2973    _Eng __e;
2974    int __n;
2975    __is >> __e >> __n;
2976    if (!__is.fail())
2977    {
2978        __x.__e_ = __e;
2979        __x.__n_ = __n;
2980    }
2981    return __is;
2982}
2983
2984typedef discard_block_engine<ranlux24_base, 223, 23> ranlux24;
2985typedef discard_block_engine<ranlux48_base, 389, 11> ranlux48;
2986
2987// independent_bits_engine
2988
2989template<class _Engine, size_t __w, class _UIntType>
2990class _LIBCPP_TEMPLATE_VIS independent_bits_engine
2991{
2992    template <class _UInt, _UInt _R0, size_t _Wp, size_t _Mp>
2993    class __get_n
2994    {
2995        static _LIBCPP_CONSTEXPR const size_t _Dt = numeric_limits<_UInt>::digits;
2996        static _LIBCPP_CONSTEXPR const size_t _Np = _Wp / _Mp + (_Wp % _Mp != 0);
2997        static _LIBCPP_CONSTEXPR const size_t _W0 = _Wp / _Np;
2998        static _LIBCPP_CONSTEXPR const _UInt _Y0 = _W0 >= _Dt ? 0 : (_R0 >> _W0) << _W0;
2999    public:
3000        static _LIBCPP_CONSTEXPR const size_t value = _R0 - _Y0 > _Y0 / _Np ? _Np + 1 : _Np;
3001    };
3002public:
3003    // types
3004    typedef _UIntType result_type;
3005
3006private:
3007    _Engine __e_;
3008
3009    static _LIBCPP_CONSTEXPR const result_type _Dt = numeric_limits<result_type>::digits;
3010    static_assert(  0 <  __w, "independent_bits_engine invalid parameters");
3011    static_assert(__w <= _Dt, "independent_bits_engine invalid parameters");
3012
3013    typedef typename _Engine::result_type _Engine_result_type;
3014    typedef typename conditional
3015        <
3016            sizeof(_Engine_result_type) <= sizeof(result_type),
3017                result_type,
3018                _Engine_result_type
3019        >::type _Working_result_type;
3020#ifdef _LIBCPP_CXX03_LANG
3021    static const _Working_result_type _Rp = _Engine::_Max - _Engine::_Min
3022                                          + _Working_result_type(1);
3023#else
3024    static _LIBCPP_CONSTEXPR const _Working_result_type _Rp = _Engine::max() - _Engine::min()
3025                                                            + _Working_result_type(1);
3026#endif
3027    static _LIBCPP_CONSTEXPR const size_t __m = __log2<_Working_result_type, _Rp>::value;
3028    static _LIBCPP_CONSTEXPR const size_t __n = __get_n<_Working_result_type, _Rp, __w, __m>::value;
3029    static _LIBCPP_CONSTEXPR const size_t __w0 = __w / __n;
3030    static _LIBCPP_CONSTEXPR const size_t __n0 = __n - __w % __n;
3031    static _LIBCPP_CONSTEXPR const size_t _WDt = numeric_limits<_Working_result_type>::digits;
3032    static _LIBCPP_CONSTEXPR const size_t _EDt = numeric_limits<_Engine_result_type>::digits;
3033    static _LIBCPP_CONSTEXPR const _Working_result_type __y0 = __w0 >= _WDt ? 0 :
3034                                                               (_Rp >> __w0) << __w0;
3035    static _LIBCPP_CONSTEXPR const _Working_result_type __y1 = __w0 >= _WDt - 1 ? 0 :
3036                                                               (_Rp >> (__w0+1)) << (__w0+1);
3037    static _LIBCPP_CONSTEXPR const _Engine_result_type __mask0 = __w0 > 0 ?
3038                                _Engine_result_type(~0) >> (_EDt - __w0) :
3039                                _Engine_result_type(0);
3040    static _LIBCPP_CONSTEXPR const _Engine_result_type __mask1 = __w0 < _EDt - 1 ?
3041                                _Engine_result_type(~0) >> (_EDt - (__w0 + 1)) :
3042                                _Engine_result_type(~0);
3043public:
3044    static _LIBCPP_CONSTEXPR const result_type _Min = 0;
3045    static _LIBCPP_CONSTEXPR const result_type _Max = __w == _Dt ? result_type(~0) :
3046                                                      (result_type(1) << __w) - result_type(1);
3047    static_assert(_Min < _Max, "independent_bits_engine invalid parameters");
3048
3049    // engine characteristics
3050    _LIBCPP_INLINE_VISIBILITY
3051    static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
3052    _LIBCPP_INLINE_VISIBILITY
3053    static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
3054
3055    // constructors and seeding functions
3056    _LIBCPP_INLINE_VISIBILITY
3057    independent_bits_engine() {}
3058    _LIBCPP_INLINE_VISIBILITY
3059    explicit independent_bits_engine(const _Engine& __e)
3060        : __e_(__e) {}
3061#ifndef _LIBCPP_CXX03_LANG
3062    _LIBCPP_INLINE_VISIBILITY
3063    explicit independent_bits_engine(_Engine&& __e)
3064        : __e_(_VSTD::move(__e)) {}
3065#endif  // _LIBCPP_CXX03_LANG
3066    _LIBCPP_INLINE_VISIBILITY
3067    explicit independent_bits_engine(result_type __sd) : __e_(__sd) {}
3068    template<class _Sseq>
3069        _LIBCPP_INLINE_VISIBILITY
3070        explicit independent_bits_engine(_Sseq& __q,
3071        typename enable_if<__is_seed_sequence<_Sseq, independent_bits_engine>::value &&
3072                           !is_convertible<_Sseq, _Engine>::value>::type* = 0)
3073         : __e_(__q) {}
3074    _LIBCPP_INLINE_VISIBILITY
3075    void seed() {__e_.seed();}
3076    _LIBCPP_INLINE_VISIBILITY
3077    void seed(result_type __sd) {__e_.seed(__sd);}
3078    template<class _Sseq>
3079        _LIBCPP_INLINE_VISIBILITY
3080        typename enable_if
3081        <
3082            __is_seed_sequence<_Sseq, independent_bits_engine>::value,
3083            void
3084        >::type
3085        seed(_Sseq& __q) {__e_.seed(__q);}
3086
3087    // generating functions
3088    _LIBCPP_INLINE_VISIBILITY
3089    result_type operator()() {return __eval(integral_constant<bool, _Rp != 0>());}
3090    _LIBCPP_INLINE_VISIBILITY
3091    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
3092
3093    // property functions
3094    _LIBCPP_INLINE_VISIBILITY
3095    const _Engine& base() const _NOEXCEPT {return __e_;}
3096
3097    template<class _Eng, size_t _Wp, class _UInt>
3098    friend
3099    bool
3100    operator==(
3101        const independent_bits_engine<_Eng, _Wp, _UInt>& __x,
3102        const independent_bits_engine<_Eng, _Wp, _UInt>& __y);
3103
3104    template<class _Eng, size_t _Wp, class _UInt>
3105    friend
3106    bool
3107    operator!=(
3108        const independent_bits_engine<_Eng, _Wp, _UInt>& __x,
3109        const independent_bits_engine<_Eng, _Wp, _UInt>& __y);
3110
3111    template <class _CharT, class _Traits,
3112              class _Eng, size_t _Wp, class _UInt>
3113    friend
3114    basic_ostream<_CharT, _Traits>&
3115    operator<<(basic_ostream<_CharT, _Traits>& __os,
3116               const independent_bits_engine<_Eng, _Wp, _UInt>& __x);
3117
3118    template <class _CharT, class _Traits,
3119              class _Eng, size_t _Wp, class _UInt>
3120    friend
3121    basic_istream<_CharT, _Traits>&
3122    operator>>(basic_istream<_CharT, _Traits>& __is,
3123               independent_bits_engine<_Eng, _Wp, _UInt>& __x);
3124
3125private:
3126    _LIBCPP_INLINE_VISIBILITY
3127    result_type __eval(false_type);
3128    result_type __eval(true_type);
3129
3130    template <size_t __count>
3131        _LIBCPP_INLINE_VISIBILITY
3132        static
3133        typename enable_if
3134        <
3135            __count < _Dt,
3136            result_type
3137        >::type
3138        __lshift(result_type __x) {return __x << __count;}
3139
3140    template <size_t __count>
3141        _LIBCPP_INLINE_VISIBILITY
3142        static
3143        typename enable_if
3144        <
3145            (__count >= _Dt),
3146            result_type
3147        >::type
3148        __lshift(result_type) {return result_type(0);}
3149};
3150
3151template<class _Engine, size_t __w, class _UIntType>
3152inline
3153_UIntType
3154independent_bits_engine<_Engine, __w, _UIntType>::__eval(false_type)
3155{
3156    return static_cast<result_type>(__e_() & __mask0);
3157}
3158
3159template<class _Engine, size_t __w, class _UIntType>
3160_UIntType
3161independent_bits_engine<_Engine, __w, _UIntType>::__eval(true_type)
3162{
3163    result_type _Sp = 0;
3164    for (size_t __k = 0; __k < __n0; ++__k)
3165    {
3166        _Engine_result_type __u;
3167        do
3168        {
3169            __u = __e_() - _Engine::min();
3170        } while (__u >= __y0);
3171        _Sp = static_cast<result_type>(__lshift<__w0>(_Sp) + (__u & __mask0));
3172    }
3173    for (size_t __k = __n0; __k < __n; ++__k)
3174    {
3175        _Engine_result_type __u;
3176        do
3177        {
3178            __u = __e_() - _Engine::min();
3179        } while (__u >= __y1);
3180        _Sp = static_cast<result_type>(__lshift<__w0+1>(_Sp) + (__u & __mask1));
3181    }
3182    return _Sp;
3183}
3184
3185template<class _Eng, size_t _Wp, class _UInt>
3186inline _LIBCPP_INLINE_VISIBILITY
3187bool
3188operator==(
3189    const independent_bits_engine<_Eng, _Wp, _UInt>& __x,
3190    const independent_bits_engine<_Eng, _Wp, _UInt>& __y)
3191{
3192    return __x.base() == __y.base();
3193}
3194
3195template<class _Eng, size_t _Wp, class _UInt>
3196inline _LIBCPP_INLINE_VISIBILITY
3197bool
3198operator!=(
3199    const independent_bits_engine<_Eng, _Wp, _UInt>& __x,
3200    const independent_bits_engine<_Eng, _Wp, _UInt>& __y)
3201{
3202    return !(__x == __y);
3203}
3204
3205template <class _CharT, class _Traits,
3206          class _Eng, size_t _Wp, class _UInt>
3207basic_ostream<_CharT, _Traits>&
3208operator<<(basic_ostream<_CharT, _Traits>& __os,
3209           const independent_bits_engine<_Eng, _Wp, _UInt>& __x)
3210{
3211    return __os << __x.base();
3212}
3213
3214template <class _CharT, class _Traits,
3215          class _Eng, size_t _Wp, class _UInt>
3216basic_istream<_CharT, _Traits>&
3217operator>>(basic_istream<_CharT, _Traits>& __is,
3218           independent_bits_engine<_Eng, _Wp, _UInt>& __x)
3219{
3220    _Eng __e;
3221    __is >> __e;
3222    if (!__is.fail())
3223        __x.__e_ = __e;
3224    return __is;
3225}
3226
3227// shuffle_order_engine
3228
3229template <uint64_t _Xp, uint64_t _Yp>
3230struct __ugcd
3231{
3232    static _LIBCPP_CONSTEXPR const uint64_t value = __ugcd<_Yp, _Xp % _Yp>::value;
3233};
3234
3235template <uint64_t _Xp>
3236struct __ugcd<_Xp, 0>
3237{
3238    static _LIBCPP_CONSTEXPR const uint64_t value = _Xp;
3239};
3240
3241template <uint64_t _Np, uint64_t _Dp>
3242class __uratio
3243{
3244    static_assert(_Dp != 0, "__uratio divide by 0");
3245    static _LIBCPP_CONSTEXPR const uint64_t __gcd = __ugcd<_Np, _Dp>::value;
3246public:
3247    static _LIBCPP_CONSTEXPR const uint64_t num = _Np / __gcd;
3248    static _LIBCPP_CONSTEXPR const uint64_t den = _Dp / __gcd;
3249
3250    typedef __uratio<num, den> type;
3251};
3252
3253template<class _Engine, size_t __k>
3254class _LIBCPP_TEMPLATE_VIS shuffle_order_engine
3255{
3256    static_assert(0 < __k, "shuffle_order_engine invalid parameters");
3257public:
3258    // types
3259    typedef typename _Engine::result_type result_type;
3260
3261private:
3262    _Engine __e_;
3263    result_type _V_[__k];
3264    result_type _Y_;
3265
3266public:
3267    // engine characteristics
3268    static _LIBCPP_CONSTEXPR const size_t table_size = __k;
3269
3270#ifdef _LIBCPP_CXX03_LANG
3271    static const result_type _Min = _Engine::_Min;
3272    static const result_type _Max = _Engine::_Max;
3273#else
3274    static _LIBCPP_CONSTEXPR const result_type _Min = _Engine::min();
3275    static _LIBCPP_CONSTEXPR const result_type _Max = _Engine::max();
3276#endif
3277    static_assert(_Min < _Max, "shuffle_order_engine invalid parameters");
3278    _LIBCPP_INLINE_VISIBILITY
3279    static _LIBCPP_CONSTEXPR result_type min() { return _Min; }
3280    _LIBCPP_INLINE_VISIBILITY
3281    static _LIBCPP_CONSTEXPR result_type max() { return _Max; }
3282
3283    static _LIBCPP_CONSTEXPR const unsigned long long _Rp = _Max - _Min + 1ull;
3284
3285    // constructors and seeding functions
3286    _LIBCPP_INLINE_VISIBILITY
3287    shuffle_order_engine() {__init();}
3288    _LIBCPP_INLINE_VISIBILITY
3289    explicit shuffle_order_engine(const _Engine& __e)
3290        : __e_(__e) {__init();}
3291#ifndef _LIBCPP_CXX03_LANG
3292    _LIBCPP_INLINE_VISIBILITY
3293    explicit shuffle_order_engine(_Engine&& __e)
3294        : __e_(_VSTD::move(__e)) {__init();}
3295#endif  // _LIBCPP_CXX03_LANG
3296    _LIBCPP_INLINE_VISIBILITY
3297    explicit shuffle_order_engine(result_type __sd) : __e_(__sd) {__init();}
3298    template<class _Sseq>
3299        _LIBCPP_INLINE_VISIBILITY
3300        explicit shuffle_order_engine(_Sseq& __q,
3301        typename enable_if<__is_seed_sequence<_Sseq, shuffle_order_engine>::value &&
3302                           !is_convertible<_Sseq, _Engine>::value>::type* = 0)
3303         : __e_(__q) {__init();}
3304    _LIBCPP_INLINE_VISIBILITY
3305    void seed() {__e_.seed(); __init();}
3306    _LIBCPP_INLINE_VISIBILITY
3307    void seed(result_type __sd) {__e_.seed(__sd); __init();}
3308    template<class _Sseq>
3309        _LIBCPP_INLINE_VISIBILITY
3310        typename enable_if
3311        <
3312            __is_seed_sequence<_Sseq, shuffle_order_engine>::value,
3313            void
3314        >::type
3315        seed(_Sseq& __q) {__e_.seed(__q); __init();}
3316
3317    // generating functions
3318    _LIBCPP_INLINE_VISIBILITY
3319    result_type operator()() {return __eval(integral_constant<bool, _Rp != 0>());}
3320    _LIBCPP_INLINE_VISIBILITY
3321    void discard(unsigned long long __z) {for (; __z; --__z) operator()();}
3322
3323    // property functions
3324    _LIBCPP_INLINE_VISIBILITY
3325    const _Engine& base() const _NOEXCEPT {return __e_;}
3326
3327private:
3328    template<class _Eng, size_t _Kp>
3329    friend
3330    bool
3331    operator==(
3332        const shuffle_order_engine<_Eng, _Kp>& __x,
3333        const shuffle_order_engine<_Eng, _Kp>& __y);
3334
3335    template<class _Eng, size_t _Kp>
3336    friend
3337    bool
3338    operator!=(
3339        const shuffle_order_engine<_Eng, _Kp>& __x,
3340        const shuffle_order_engine<_Eng, _Kp>& __y);
3341
3342    template <class _CharT, class _Traits,
3343              class _Eng, size_t _Kp>
3344    friend
3345    basic_ostream<_CharT, _Traits>&
3346    operator<<(basic_ostream<_CharT, _Traits>& __os,
3347               const shuffle_order_engine<_Eng, _Kp>& __x);
3348
3349    template <class _CharT, class _Traits,
3350              class _Eng, size_t _Kp>
3351    friend
3352    basic_istream<_CharT, _Traits>&
3353    operator>>(basic_istream<_CharT, _Traits>& __is,
3354               shuffle_order_engine<_Eng, _Kp>& __x);
3355
3356    _LIBCPP_INLINE_VISIBILITY
3357    void __init()
3358    {
3359        for (size_t __i = 0; __i < __k; ++__i)
3360            _V_[__i] = __e_();
3361        _Y_ = __e_();
3362    }
3363
3364    _LIBCPP_INLINE_VISIBILITY
3365    result_type __eval(false_type) {return __eval2(integral_constant<bool, __k & 1>());}
3366    _LIBCPP_INLINE_VISIBILITY
3367    result_type __eval(true_type) {return __eval(__uratio<__k, _Rp>());}
3368
3369    _LIBCPP_INLINE_VISIBILITY
3370    result_type __eval2(false_type) {return __eval(__uratio<__k/2, 0x8000000000000000ull>());}
3371    _LIBCPP_INLINE_VISIBILITY
3372    result_type __eval2(true_type) {return __evalf<__k, 0>();}
3373
3374    template <uint64_t _Np, uint64_t _Dp>
3375        _LIBCPP_INLINE_VISIBILITY
3376        typename enable_if
3377        <
3378            (__uratio<_Np, _Dp>::num > 0xFFFFFFFFFFFFFFFFull / (_Max - _Min)),
3379            result_type
3380        >::type
3381        __eval(__uratio<_Np, _Dp>)
3382            {return __evalf<__uratio<_Np, _Dp>::num, __uratio<_Np, _Dp>::den>();}
3383
3384    template <uint64_t _Np, uint64_t _Dp>
3385        _LIBCPP_INLINE_VISIBILITY
3386        typename enable_if
3387        <
3388            __uratio<_Np, _Dp>::num <= 0xFFFFFFFFFFFFFFFFull / (_Max - _Min),
3389            result_type
3390        >::type
3391        __eval(__uratio<_Np, _Dp>)
3392        {
3393            const size_t __j = static_cast<size_t>(__uratio<_Np, _Dp>::num * (_Y_ - _Min)
3394                                                   / __uratio<_Np, _Dp>::den);
3395            _Y_ = _V_[__j];
3396            _V_[__j] = __e_();
3397            return _Y_;
3398        }
3399
3400    template <uint64_t __n, uint64_t __d>
3401        _LIBCPP_INLINE_VISIBILITY
3402        result_type __evalf()
3403        {
3404            const double _Fp = __d == 0 ?
3405                __n / (2. * 0x8000000000000000ull) :
3406                __n / (double)__d;
3407            const size_t __j = static_cast<size_t>(_Fp * (_Y_ - _Min));
3408            _Y_ = _V_[__j];
3409            _V_[__j] = __e_();
3410            return _Y_;
3411        }
3412};
3413
3414template<class _Engine, size_t __k>
3415    _LIBCPP_CONSTEXPR const size_t shuffle_order_engine<_Engine, __k>::table_size;
3416
3417template<class _Eng, size_t _Kp>
3418bool
3419operator==(
3420    const shuffle_order_engine<_Eng, _Kp>& __x,
3421    const shuffle_order_engine<_Eng, _Kp>& __y)
3422{
3423    return __x._Y_ == __y._Y_ && _VSTD::equal(__x._V_, __x._V_ + _Kp, __y._V_) &&
3424           __x.__e_ == __y.__e_;
3425}
3426
3427template<class _Eng, size_t _Kp>
3428inline _LIBCPP_INLINE_VISIBILITY
3429bool
3430operator!=(
3431    const shuffle_order_engine<_Eng, _Kp>& __x,
3432    const shuffle_order_engine<_Eng, _Kp>& __y)
3433{
3434    return !(__x == __y);
3435}
3436
3437template <class _CharT, class _Traits,
3438          class _Eng, size_t _Kp>
3439basic_ostream<_CharT, _Traits>&
3440operator<<(basic_ostream<_CharT, _Traits>& __os,
3441           const shuffle_order_engine<_Eng, _Kp>& __x)
3442{
3443    __save_flags<_CharT, _Traits> __lx(__os);
3444    __os.flags(ios_base::dec | ios_base::left);
3445    _CharT __sp = __os.widen(' ');
3446    __os.fill(__sp);
3447    __os << __x.__e_ << __sp << __x._V_[0];
3448    for (size_t __i = 1; __i < _Kp; ++__i)
3449        __os << __sp << __x._V_[__i];
3450    return __os << __sp << __x._Y_;
3451}
3452
3453template <class _CharT, class _Traits,
3454          class _Eng, size_t _Kp>
3455basic_istream<_CharT, _Traits>&
3456operator>>(basic_istream<_CharT, _Traits>& __is,
3457           shuffle_order_engine<_Eng, _Kp>& __x)
3458{
3459    typedef typename shuffle_order_engine<_Eng, _Kp>::result_type result_type;
3460    __save_flags<_CharT, _Traits> __lx(__is);
3461    __is.flags(ios_base::dec | ios_base::skipws);
3462    _Eng __e;
3463    result_type _Vp[_Kp+1];
3464    __is >> __e;
3465    for (size_t __i = 0; __i < _Kp+1; ++__i)
3466        __is >> _Vp[__i];
3467    if (!__is.fail())
3468    {
3469        __x.__e_ = __e;
3470        for (size_t __i = 0; __i < _Kp; ++__i)
3471            __x._V_[__i] = _Vp[__i];
3472        __x._Y_ = _Vp[_Kp];
3473    }
3474    return __is;
3475}
3476
3477typedef shuffle_order_engine<minstd_rand0, 256>                         knuth_b;
3478
3479// random_device
3480
3481class _LIBCPP_TYPE_VIS random_device
3482{
3483#ifdef _LIBCPP_USING_DEV_RANDOM
3484    int __f_;
3485#endif // defined(_LIBCPP_USING_DEV_RANDOM)
3486public:
3487    // types
3488    typedef unsigned result_type;
3489
3490    // generator characteristics
3491    static _LIBCPP_CONSTEXPR const result_type _Min = 0;
3492    static _LIBCPP_CONSTEXPR const result_type _Max = 0xFFFFFFFFu;
3493
3494    _LIBCPP_INLINE_VISIBILITY
3495    static _LIBCPP_CONSTEXPR result_type min() { return _Min;}
3496    _LIBCPP_INLINE_VISIBILITY
3497    static _LIBCPP_CONSTEXPR result_type max() { return _Max;}
3498
3499    // constructors
3500    explicit random_device(const string& __token = "/dev/urandom");
3501    ~random_device();
3502
3503    // generating functions
3504    result_type operator()();
3505
3506    // property functions
3507    double entropy() const _NOEXCEPT;
3508
3509private:
3510    // no copy functions
3511    random_device(const random_device&); // = delete;
3512    random_device& operator=(const random_device&); // = delete;
3513};
3514
3515// seed_seq
3516
3517class _LIBCPP_TEMPLATE_VIS seed_seq
3518{
3519public:
3520    // types
3521    typedef uint32_t result_type;
3522
3523private:
3524    vector<result_type> __v_;
3525
3526    template<class _InputIterator>
3527        void init(_InputIterator __first, _InputIterator __last);
3528public:
3529    // constructors
3530    _LIBCPP_INLINE_VISIBILITY
3531    seed_seq() _NOEXCEPT {}
3532#ifndef _LIBCPP_CXX03_LANG
3533    template<class _Tp>
3534        _LIBCPP_INLINE_VISIBILITY
3535        seed_seq(initializer_list<_Tp> __il) {init(__il.begin(), __il.end());}
3536#endif  // _LIBCPP_CXX03_LANG
3537
3538    template<class _InputIterator>
3539        _LIBCPP_INLINE_VISIBILITY
3540        seed_seq(_InputIterator __first, _InputIterator __last)
3541             {init(__first, __last);}
3542
3543    // generating functions
3544    template<class _RandomAccessIterator>
3545        void generate(_RandomAccessIterator __first, _RandomAccessIterator __last);
3546
3547    // property functions
3548    _LIBCPP_INLINE_VISIBILITY
3549    size_t size() const _NOEXCEPT {return __v_.size();}
3550    template<class _OutputIterator>
3551        _LIBCPP_INLINE_VISIBILITY
3552        void param(_OutputIterator __dest) const
3553            {_VSTD::copy(__v_.begin(), __v_.end(), __dest);}
3554
3555private:
3556    // no copy functions
3557    seed_seq(const seed_seq&); // = delete;
3558    void operator=(const seed_seq&); // = delete;
3559
3560    _LIBCPP_INLINE_VISIBILITY
3561    static result_type _Tp(result_type __x) {return __x ^ (__x >> 27);}
3562};
3563
3564template<class _InputIterator>
3565void
3566seed_seq::init(_InputIterator __first, _InputIterator __last)
3567{
3568    for (_InputIterator __s = __first; __s != __last; ++__s)
3569        __v_.push_back(*__s & 0xFFFFFFFF);
3570}
3571
3572template<class _RandomAccessIterator>
3573void
3574seed_seq::generate(_RandomAccessIterator __first, _RandomAccessIterator __last)
3575{
3576    if (__first != __last)
3577    {
3578        _VSTD::fill(__first, __last, 0x8b8b8b8b);
3579        const size_t __n = static_cast<size_t>(__last - __first);
3580        const size_t __s = __v_.size();
3581        const size_t __t = (__n >= 623) ? 11
3582                         : (__n >= 68) ? 7
3583                         : (__n >= 39) ? 5
3584                         : (__n >= 7)  ? 3
3585                         : (__n - 1) / 2;
3586        const size_t __p = (__n - __t) / 2;
3587        const size_t __q = __p + __t;
3588        const size_t __m = _VSTD::max(__s + 1, __n);
3589        // __k = 0;
3590        {
3591            result_type __r = 1664525 * _Tp(__first[0] ^ __first[__p]
3592                                                      ^  __first[__n - 1]);
3593            __first[__p] += __r;
3594            __r += __s;
3595            __first[__q] += __r;
3596            __first[0] = __r;
3597        }
3598        for (size_t __k = 1; __k <= __s; ++__k)
3599        {
3600            const size_t __kmodn = __k % __n;
3601            const size_t __kpmodn = (__k + __p) % __n;
3602            result_type __r = 1664525 * _Tp(__first[__kmodn] ^ __first[__kpmodn]
3603                                           ^ __first[(__k - 1) % __n]);
3604            __first[__kpmodn] += __r;
3605            __r +=  __kmodn + __v_[__k-1];
3606            __first[(__k + __q) % __n] += __r;
3607            __first[__kmodn] = __r;
3608        }
3609        for (size_t __k = __s + 1; __k < __m; ++__k)
3610        {
3611            const size_t __kmodn = __k % __n;
3612            const size_t __kpmodn = (__k + __p) % __n;
3613            result_type __r = 1664525 * _Tp(__first[__kmodn] ^ __first[__kpmodn]
3614                                           ^ __first[(__k - 1) % __n]);
3615            __first[__kpmodn] += __r;
3616            __r +=  __kmodn;
3617            __first[(__k + __q) % __n] += __r;
3618            __first[__kmodn] = __r;
3619        }
3620        for (size_t __k = __m; __k < __m + __n; ++__k)
3621        {
3622            const size_t __kmodn = __k % __n;
3623            const size_t __kpmodn = (__k + __p) % __n;
3624            result_type __r = 1566083941 * _Tp(__first[__kmodn] +
3625                                              __first[__kpmodn] +
3626                                              __first[(__k - 1) % __n]);
3627            __first[__kpmodn] ^= __r;
3628            __r -= __kmodn;
3629            __first[(__k + __q) % __n] ^= __r;
3630            __first[__kmodn] = __r;
3631        }
3632    }
3633}
3634
3635// generate_canonical
3636
3637template<class _RealType, size_t __bits, class _URNG>
3638_RealType
3639generate_canonical(_URNG& __g)
3640{
3641    const size_t _Dt = numeric_limits<_RealType>::digits;
3642    const size_t __b = _Dt < __bits ? _Dt : __bits;
3643#ifdef _LIBCPP_CXX03_LANG
3644    const size_t __logR = __log2<uint64_t, _URNG::_Max - _URNG::_Min + uint64_t(1)>::value;
3645#else
3646    const size_t __logR = __log2<uint64_t, _URNG::max() - _URNG::min() + uint64_t(1)>::value;
3647#endif
3648    const size_t __k = __b / __logR + (__b % __logR != 0) + (__b == 0);
3649    const _RealType _Rp = _URNG::max() - _URNG::min() + _RealType(1);
3650    _RealType __base = _Rp;
3651    _RealType _Sp = __g() - _URNG::min();
3652    for (size_t __i = 1; __i < __k; ++__i, __base *= _Rp)
3653        _Sp += (__g() - _URNG::min()) * __base;
3654    return _Sp / __base;
3655}
3656
3657// uniform_int_distribution
3658
3659// in <algorithm>
3660
3661template <class _CharT, class _Traits, class _IT>
3662basic_ostream<_CharT, _Traits>&
3663operator<<(basic_ostream<_CharT, _Traits>& __os,
3664           const uniform_int_distribution<_IT>& __x)
3665{
3666    __save_flags<_CharT, _Traits> __lx(__os);
3667    __os.flags(ios_base::dec | ios_base::left);
3668    _CharT __sp = __os.widen(' ');
3669    __os.fill(__sp);
3670    return __os << __x.a() << __sp << __x.b();
3671}
3672
3673template <class _CharT, class _Traits, class _IT>
3674basic_istream<_CharT, _Traits>&
3675operator>>(basic_istream<_CharT, _Traits>& __is,
3676           uniform_int_distribution<_IT>& __x)
3677{
3678    typedef uniform_int_distribution<_IT> _Eng;
3679    typedef typename _Eng::result_type result_type;
3680    typedef typename _Eng::param_type param_type;
3681    __save_flags<_CharT, _Traits> __lx(__is);
3682    __is.flags(ios_base::dec | ios_base::skipws);
3683    result_type __a;
3684    result_type __b;
3685    __is >> __a >> __b;
3686    if (!__is.fail())
3687        __x.param(param_type(__a, __b));
3688    return __is;
3689}
3690
3691// uniform_real_distribution
3692
3693template<class _RealType = double>
3694class _LIBCPP_TEMPLATE_VIS uniform_real_distribution
3695{
3696public:
3697    // types
3698    typedef _RealType result_type;
3699
3700    class _LIBCPP_TEMPLATE_VIS param_type
3701    {
3702        result_type __a_;
3703        result_type __b_;
3704    public:
3705        typedef uniform_real_distribution distribution_type;
3706
3707        _LIBCPP_INLINE_VISIBILITY
3708        explicit param_type(result_type __a = 0,
3709                            result_type __b = 1)
3710            : __a_(__a), __b_(__b) {}
3711
3712        _LIBCPP_INLINE_VISIBILITY
3713        result_type a() const {return __a_;}
3714        _LIBCPP_INLINE_VISIBILITY
3715        result_type b() const {return __b_;}
3716
3717        friend _LIBCPP_INLINE_VISIBILITY
3718        bool operator==(const param_type& __x, const param_type& __y)
3719            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
3720        friend _LIBCPP_INLINE_VISIBILITY
3721        bool operator!=(const param_type& __x, const param_type& __y)
3722            {return !(__x == __y);}
3723    };
3724
3725private:
3726    param_type __p_;
3727
3728public:
3729    // constructors and reset functions
3730    _LIBCPP_INLINE_VISIBILITY
3731    explicit uniform_real_distribution(result_type __a = 0, result_type __b = 1)
3732        : __p_(param_type(__a, __b)) {}
3733    _LIBCPP_INLINE_VISIBILITY
3734    explicit uniform_real_distribution(const param_type& __p) : __p_(__p) {}
3735    _LIBCPP_INLINE_VISIBILITY
3736    void reset() {}
3737
3738    // generating functions
3739    template<class _URNG>
3740        _LIBCPP_INLINE_VISIBILITY
3741        result_type operator()(_URNG& __g)
3742        {return (*this)(__g, __p_);}
3743    template<class _URNG> _LIBCPP_INLINE_VISIBILITY result_type operator()(_URNG& __g, const param_type& __p);
3744
3745    // property functions
3746    _LIBCPP_INLINE_VISIBILITY
3747    result_type a() const {return __p_.a();}
3748    _LIBCPP_INLINE_VISIBILITY
3749    result_type b() const {return __p_.b();}
3750
3751    _LIBCPP_INLINE_VISIBILITY
3752    param_type param() const {return __p_;}
3753    _LIBCPP_INLINE_VISIBILITY
3754    void param(const param_type& __p) {__p_ = __p;}
3755
3756    _LIBCPP_INLINE_VISIBILITY
3757    result_type min() const {return a();}
3758    _LIBCPP_INLINE_VISIBILITY
3759    result_type max() const {return b();}
3760
3761    friend _LIBCPP_INLINE_VISIBILITY
3762        bool operator==(const uniform_real_distribution& __x,
3763                        const uniform_real_distribution& __y)
3764        {return __x.__p_ == __y.__p_;}
3765    friend _LIBCPP_INLINE_VISIBILITY
3766        bool operator!=(const uniform_real_distribution& __x,
3767                        const uniform_real_distribution& __y)
3768        {return !(__x == __y);}
3769};
3770
3771template<class _RealType>
3772template<class _URNG>
3773inline
3774typename uniform_real_distribution<_RealType>::result_type
3775uniform_real_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
3776{
3777    return (__p.b() - __p.a())
3778        * _VSTD::generate_canonical<_RealType, numeric_limits<_RealType>::digits>(__g)
3779        + __p.a();
3780}
3781
3782template <class _CharT, class _Traits, class _RT>
3783basic_ostream<_CharT, _Traits>&
3784operator<<(basic_ostream<_CharT, _Traits>& __os,
3785           const uniform_real_distribution<_RT>& __x)
3786{
3787    __save_flags<_CharT, _Traits> __lx(__os);
3788    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
3789               ios_base::scientific);
3790    _CharT __sp = __os.widen(' ');
3791    __os.fill(__sp);
3792    return __os << __x.a() << __sp << __x.b();
3793}
3794
3795template <class _CharT, class _Traits, class _RT>
3796basic_istream<_CharT, _Traits>&
3797operator>>(basic_istream<_CharT, _Traits>& __is,
3798           uniform_real_distribution<_RT>& __x)
3799{
3800    typedef uniform_real_distribution<_RT> _Eng;
3801    typedef typename _Eng::result_type result_type;
3802    typedef typename _Eng::param_type param_type;
3803    __save_flags<_CharT, _Traits> __lx(__is);
3804    __is.flags(ios_base::dec | ios_base::skipws);
3805    result_type __a;
3806    result_type __b;
3807    __is >> __a >> __b;
3808    if (!__is.fail())
3809        __x.param(param_type(__a, __b));
3810    return __is;
3811}
3812
3813// bernoulli_distribution
3814
3815class _LIBCPP_TEMPLATE_VIS bernoulli_distribution
3816{
3817public:
3818    // types
3819    typedef bool result_type;
3820
3821    class _LIBCPP_TEMPLATE_VIS param_type
3822    {
3823        double __p_;
3824    public:
3825        typedef bernoulli_distribution distribution_type;
3826
3827        _LIBCPP_INLINE_VISIBILITY
3828        explicit param_type(double __p = 0.5) : __p_(__p) {}
3829
3830        _LIBCPP_INLINE_VISIBILITY
3831        double p() const {return __p_;}
3832
3833        friend _LIBCPP_INLINE_VISIBILITY
3834            bool operator==(const param_type& __x, const param_type& __y)
3835            {return __x.__p_ == __y.__p_;}
3836        friend _LIBCPP_INLINE_VISIBILITY
3837            bool operator!=(const param_type& __x, const param_type& __y)
3838            {return !(__x == __y);}
3839    };
3840
3841private:
3842    param_type __p_;
3843
3844public:
3845    // constructors and reset functions
3846    _LIBCPP_INLINE_VISIBILITY
3847    explicit bernoulli_distribution(double __p = 0.5)
3848        : __p_(param_type(__p)) {}
3849    _LIBCPP_INLINE_VISIBILITY
3850    explicit bernoulli_distribution(const param_type& __p) : __p_(__p) {}
3851    _LIBCPP_INLINE_VISIBILITY
3852    void reset() {}
3853
3854    // generating functions
3855    template<class _URNG>
3856        _LIBCPP_INLINE_VISIBILITY
3857        result_type operator()(_URNG& __g)
3858        {return (*this)(__g, __p_);}
3859    template<class _URNG> _LIBCPP_INLINE_VISIBILITY result_type operator()(_URNG& __g, const param_type& __p);
3860
3861    // property functions
3862    _LIBCPP_INLINE_VISIBILITY
3863    double p() const {return __p_.p();}
3864
3865    _LIBCPP_INLINE_VISIBILITY
3866    param_type param() const {return __p_;}
3867    _LIBCPP_INLINE_VISIBILITY
3868    void param(const param_type& __p) {__p_ = __p;}
3869
3870    _LIBCPP_INLINE_VISIBILITY
3871    result_type min() const {return false;}
3872    _LIBCPP_INLINE_VISIBILITY
3873    result_type max() const {return true;}
3874
3875    friend _LIBCPP_INLINE_VISIBILITY
3876        bool operator==(const bernoulli_distribution& __x,
3877                        const bernoulli_distribution& __y)
3878        {return __x.__p_ == __y.__p_;}
3879    friend _LIBCPP_INLINE_VISIBILITY
3880        bool operator!=(const bernoulli_distribution& __x,
3881                        const bernoulli_distribution& __y)
3882        {return !(__x == __y);}
3883};
3884
3885template<class _URNG>
3886inline
3887bernoulli_distribution::result_type
3888bernoulli_distribution::operator()(_URNG& __g, const param_type& __p)
3889{
3890    uniform_real_distribution<double> __gen;
3891    return __gen(__g) < __p.p();
3892}
3893
3894template <class _CharT, class _Traits>
3895basic_ostream<_CharT, _Traits>&
3896operator<<(basic_ostream<_CharT, _Traits>& __os, const bernoulli_distribution& __x)
3897{
3898    __save_flags<_CharT, _Traits> __lx(__os);
3899    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
3900               ios_base::scientific);
3901    _CharT __sp = __os.widen(' ');
3902    __os.fill(__sp);
3903    return __os << __x.p();
3904}
3905
3906template <class _CharT, class _Traits>
3907basic_istream<_CharT, _Traits>&
3908operator>>(basic_istream<_CharT, _Traits>& __is, bernoulli_distribution& __x)
3909{
3910    typedef bernoulli_distribution _Eng;
3911    typedef typename _Eng::param_type param_type;
3912    __save_flags<_CharT, _Traits> __lx(__is);
3913    __is.flags(ios_base::dec | ios_base::skipws);
3914    double __p;
3915    __is >> __p;
3916    if (!__is.fail())
3917        __x.param(param_type(__p));
3918    return __is;
3919}
3920
3921// binomial_distribution
3922
3923template<class _IntType = int>
3924class _LIBCPP_TEMPLATE_VIS binomial_distribution
3925{
3926public:
3927    // types
3928    typedef _IntType result_type;
3929
3930    class _LIBCPP_TEMPLATE_VIS param_type
3931    {
3932        result_type __t_;
3933        double __p_;
3934        double __pr_;
3935        double __odds_ratio_;
3936        result_type __r0_;
3937    public:
3938        typedef binomial_distribution distribution_type;
3939
3940        explicit param_type(result_type __t = 1, double __p = 0.5);
3941
3942        _LIBCPP_INLINE_VISIBILITY
3943        result_type t() const {return __t_;}
3944        _LIBCPP_INLINE_VISIBILITY
3945        double p() const {return __p_;}
3946
3947        friend _LIBCPP_INLINE_VISIBILITY
3948            bool operator==(const param_type& __x, const param_type& __y)
3949            {return __x.__t_ == __y.__t_ && __x.__p_ == __y.__p_;}
3950        friend _LIBCPP_INLINE_VISIBILITY
3951            bool operator!=(const param_type& __x, const param_type& __y)
3952            {return !(__x == __y);}
3953
3954        friend class binomial_distribution;
3955    };
3956
3957private:
3958    param_type __p_;
3959
3960public:
3961    // constructors and reset functions
3962    _LIBCPP_INLINE_VISIBILITY
3963    explicit binomial_distribution(result_type __t = 1, double __p = 0.5)
3964        : __p_(param_type(__t, __p)) {}
3965    _LIBCPP_INLINE_VISIBILITY
3966    explicit binomial_distribution(const param_type& __p) : __p_(__p) {}
3967    _LIBCPP_INLINE_VISIBILITY
3968    void reset() {}
3969
3970    // generating functions
3971    template<class _URNG>
3972        _LIBCPP_INLINE_VISIBILITY
3973        result_type operator()(_URNG& __g)
3974        {return (*this)(__g, __p_);}
3975    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
3976
3977    // property functions
3978    _LIBCPP_INLINE_VISIBILITY
3979    result_type t() const {return __p_.t();}
3980    _LIBCPP_INLINE_VISIBILITY
3981    double p() const {return __p_.p();}
3982
3983    _LIBCPP_INLINE_VISIBILITY
3984    param_type param() const {return __p_;}
3985    _LIBCPP_INLINE_VISIBILITY
3986    void param(const param_type& __p) {__p_ = __p;}
3987
3988    _LIBCPP_INLINE_VISIBILITY
3989    result_type min() const {return 0;}
3990    _LIBCPP_INLINE_VISIBILITY
3991    result_type max() const {return t();}
3992
3993    friend _LIBCPP_INLINE_VISIBILITY
3994        bool operator==(const binomial_distribution& __x,
3995                        const binomial_distribution& __y)
3996        {return __x.__p_ == __y.__p_;}
3997    friend _LIBCPP_INLINE_VISIBILITY
3998        bool operator!=(const binomial_distribution& __x,
3999                        const binomial_distribution& __y)
4000        {return !(__x == __y);}
4001};
4002
4003#ifndef _LIBCPP_MSVCRT
4004extern "C" double lgamma_r(double, int *);
4005#endif
4006
4007inline _LIBCPP_INLINE_VISIBILITY double __libcpp_lgamma(double __d) {
4008#if defined(_LIBCPP_MSVCRT)
4009  return lgamma(__d);
4010#else
4011  int __sign;
4012  return lgamma_r(__d, &__sign);
4013#endif
4014}
4015
4016template<class _IntType>
4017binomial_distribution<_IntType>::param_type::param_type(const result_type __t, const double __p)
4018    : __t_(__t), __p_(__p)
4019{
4020    if (0 < __p_ && __p_ < 1)
4021    {
4022        __r0_ = static_cast<result_type>((__t_ + 1) * __p_);
4023        __pr_ = _VSTD::exp(__libcpp_lgamma(__t_ + 1.) -
4024                           __libcpp_lgamma(__r0_ + 1.) -
4025                           __libcpp_lgamma(__t_ - __r0_ + 1.) + __r0_ * _VSTD::log(__p_) +
4026                           (__t_ - __r0_) * _VSTD::log(1 - __p_));
4027        __odds_ratio_ = __p_ / (1 - __p_);
4028    }
4029}
4030
4031// Reference: Kemp, C.D. (1986). `A modal method for generating binomial
4032//           variables', Commun. Statist. - Theor. Meth. 15(3), 805-813.
4033template<class _IntType>
4034template<class _URNG>
4035_IntType
4036binomial_distribution<_IntType>::operator()(_URNG& __g, const param_type& __pr)
4037{
4038    if (__pr.__t_ == 0 || __pr.__p_ == 0)
4039        return 0;
4040    if (__pr.__p_ == 1)
4041        return __pr.__t_;
4042    uniform_real_distribution<double> __gen;
4043    double __u = __gen(__g) - __pr.__pr_;
4044    if (__u < 0)
4045        return __pr.__r0_;
4046    double __pu = __pr.__pr_;
4047    double __pd = __pu;
4048    result_type __ru = __pr.__r0_;
4049    result_type __rd = __ru;
4050    while (true)
4051    {
4052        if (__rd >= 1)
4053        {
4054            __pd *= __rd / (__pr.__odds_ratio_ * (__pr.__t_ - __rd + 1));
4055            __u -= __pd;
4056            if (__u < 0)
4057                return __rd - 1;
4058        }
4059        if ( __rd != 0 )
4060            --__rd;
4061        ++__ru;
4062        if (__ru <= __pr.__t_)
4063        {
4064            __pu *= (__pr.__t_ - __ru + 1) * __pr.__odds_ratio_ / __ru;
4065            __u -= __pu;
4066            if (__u < 0)
4067                return __ru;
4068        }
4069    }
4070}
4071
4072template <class _CharT, class _Traits, class _IntType>
4073basic_ostream<_CharT, _Traits>&
4074operator<<(basic_ostream<_CharT, _Traits>& __os,
4075           const binomial_distribution<_IntType>& __x)
4076{
4077    __save_flags<_CharT, _Traits> __lx(__os);
4078    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
4079               ios_base::scientific);
4080    _CharT __sp = __os.widen(' ');
4081    __os.fill(__sp);
4082    return __os << __x.t() << __sp << __x.p();
4083}
4084
4085template <class _CharT, class _Traits, class _IntType>
4086basic_istream<_CharT, _Traits>&
4087operator>>(basic_istream<_CharT, _Traits>& __is,
4088           binomial_distribution<_IntType>& __x)
4089{
4090    typedef binomial_distribution<_IntType> _Eng;
4091    typedef typename _Eng::result_type result_type;
4092    typedef typename _Eng::param_type param_type;
4093    __save_flags<_CharT, _Traits> __lx(__is);
4094    __is.flags(ios_base::dec | ios_base::skipws);
4095    result_type __t;
4096    double __p;
4097    __is >> __t >> __p;
4098    if (!__is.fail())
4099        __x.param(param_type(__t, __p));
4100    return __is;
4101}
4102
4103// exponential_distribution
4104
4105template<class _RealType = double>
4106class _LIBCPP_TEMPLATE_VIS exponential_distribution
4107{
4108public:
4109    // types
4110    typedef _RealType result_type;
4111
4112    class _LIBCPP_TEMPLATE_VIS param_type
4113    {
4114        result_type __lambda_;
4115    public:
4116        typedef exponential_distribution distribution_type;
4117
4118        _LIBCPP_INLINE_VISIBILITY
4119        explicit param_type(result_type __lambda = 1) : __lambda_(__lambda) {}
4120
4121        _LIBCPP_INLINE_VISIBILITY
4122        result_type lambda() const {return __lambda_;}
4123
4124        friend _LIBCPP_INLINE_VISIBILITY
4125            bool operator==(const param_type& __x, const param_type& __y)
4126            {return __x.__lambda_ == __y.__lambda_;}
4127        friend _LIBCPP_INLINE_VISIBILITY
4128            bool operator!=(const param_type& __x, const param_type& __y)
4129            {return !(__x == __y);}
4130    };
4131
4132private:
4133    param_type __p_;
4134
4135public:
4136    // constructors and reset functions
4137    _LIBCPP_INLINE_VISIBILITY
4138    explicit exponential_distribution(result_type __lambda = 1)
4139        : __p_(param_type(__lambda)) {}
4140    _LIBCPP_INLINE_VISIBILITY
4141    explicit exponential_distribution(const param_type& __p) : __p_(__p) {}
4142    _LIBCPP_INLINE_VISIBILITY
4143    void reset() {}
4144
4145    // generating functions
4146    template<class _URNG>
4147        _LIBCPP_INLINE_VISIBILITY
4148        result_type operator()(_URNG& __g)
4149        {return (*this)(__g, __p_);}
4150    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
4151
4152    // property functions
4153    _LIBCPP_INLINE_VISIBILITY
4154    result_type lambda() const {return __p_.lambda();}
4155
4156    _LIBCPP_INLINE_VISIBILITY
4157    param_type param() const {return __p_;}
4158    _LIBCPP_INLINE_VISIBILITY
4159    void param(const param_type& __p) {__p_ = __p;}
4160
4161    _LIBCPP_INLINE_VISIBILITY
4162    result_type min() const {return 0;}
4163    _LIBCPP_INLINE_VISIBILITY
4164    result_type max() const {return numeric_limits<result_type>::infinity();}
4165
4166    friend _LIBCPP_INLINE_VISIBILITY
4167        bool operator==(const exponential_distribution& __x,
4168                        const exponential_distribution& __y)
4169        {return __x.__p_ == __y.__p_;}
4170    friend _LIBCPP_INLINE_VISIBILITY
4171        bool operator!=(const exponential_distribution& __x,
4172                        const exponential_distribution& __y)
4173        {return !(__x == __y);}
4174};
4175
4176template <class _RealType>
4177template<class _URNG>
4178_RealType
4179exponential_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
4180{
4181    return -_VSTD::log
4182                  (
4183                      result_type(1) -
4184                      _VSTD::generate_canonical<result_type,
4185                                       numeric_limits<result_type>::digits>(__g)
4186                  )
4187                  / __p.lambda();
4188}
4189
4190template <class _CharT, class _Traits, class _RealType>
4191basic_ostream<_CharT, _Traits>&
4192operator<<(basic_ostream<_CharT, _Traits>& __os,
4193           const exponential_distribution<_RealType>& __x)
4194{
4195    __save_flags<_CharT, _Traits> __lx(__os);
4196    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
4197               ios_base::scientific);
4198    return __os << __x.lambda();
4199}
4200
4201template <class _CharT, class _Traits, class _RealType>
4202basic_istream<_CharT, _Traits>&
4203operator>>(basic_istream<_CharT, _Traits>& __is,
4204           exponential_distribution<_RealType>& __x)
4205{
4206    typedef exponential_distribution<_RealType> _Eng;
4207    typedef typename _Eng::result_type result_type;
4208    typedef typename _Eng::param_type param_type;
4209    __save_flags<_CharT, _Traits> __lx(__is);
4210    __is.flags(ios_base::dec | ios_base::skipws);
4211    result_type __lambda;
4212    __is >> __lambda;
4213    if (!__is.fail())
4214        __x.param(param_type(__lambda));
4215    return __is;
4216}
4217
4218// normal_distribution
4219
4220template<class _RealType = double>
4221class _LIBCPP_TEMPLATE_VIS normal_distribution
4222{
4223public:
4224    // types
4225    typedef _RealType result_type;
4226
4227    class _LIBCPP_TEMPLATE_VIS param_type
4228    {
4229        result_type __mean_;
4230        result_type __stddev_;
4231    public:
4232        typedef normal_distribution distribution_type;
4233
4234        _LIBCPP_INLINE_VISIBILITY
4235        explicit param_type(result_type __mean = 0, result_type __stddev = 1)
4236            : __mean_(__mean), __stddev_(__stddev) {}
4237
4238        _LIBCPP_INLINE_VISIBILITY
4239        result_type mean() const {return __mean_;}
4240        _LIBCPP_INLINE_VISIBILITY
4241        result_type stddev() const {return __stddev_;}
4242
4243        friend _LIBCPP_INLINE_VISIBILITY
4244            bool operator==(const param_type& __x, const param_type& __y)
4245            {return __x.__mean_ == __y.__mean_ && __x.__stddev_ == __y.__stddev_;}
4246        friend _LIBCPP_INLINE_VISIBILITY
4247            bool operator!=(const param_type& __x, const param_type& __y)
4248            {return !(__x == __y);}
4249    };
4250
4251private:
4252    param_type __p_;
4253    result_type _V_;
4254    bool _V_hot_;
4255
4256public:
4257    // constructors and reset functions
4258    _LIBCPP_INLINE_VISIBILITY
4259    explicit normal_distribution(result_type __mean = 0, result_type __stddev = 1)
4260        : __p_(param_type(__mean, __stddev)), _V_hot_(false) {}
4261    _LIBCPP_INLINE_VISIBILITY
4262    explicit normal_distribution(const param_type& __p)
4263        : __p_(__p), _V_hot_(false) {}
4264    _LIBCPP_INLINE_VISIBILITY
4265    void reset() {_V_hot_ = false;}
4266
4267    // generating functions
4268    template<class _URNG>
4269        _LIBCPP_INLINE_VISIBILITY
4270        result_type operator()(_URNG& __g)
4271        {return (*this)(__g, __p_);}
4272    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
4273
4274    // property functions
4275    _LIBCPP_INLINE_VISIBILITY
4276    result_type mean() const {return __p_.mean();}
4277    _LIBCPP_INLINE_VISIBILITY
4278    result_type stddev() const {return __p_.stddev();}
4279
4280    _LIBCPP_INLINE_VISIBILITY
4281    param_type param() const {return __p_;}
4282    _LIBCPP_INLINE_VISIBILITY
4283    void param(const param_type& __p) {__p_ = __p;}
4284
4285    _LIBCPP_INLINE_VISIBILITY
4286    result_type min() const {return -numeric_limits<result_type>::infinity();}
4287    _LIBCPP_INLINE_VISIBILITY
4288    result_type max() const {return numeric_limits<result_type>::infinity();}
4289
4290    friend _LIBCPP_INLINE_VISIBILITY
4291        bool operator==(const normal_distribution& __x,
4292                        const normal_distribution& __y)
4293        {return __x.__p_ == __y.__p_ && __x._V_hot_ == __y._V_hot_ &&
4294                (!__x._V_hot_ || __x._V_ == __y._V_);}
4295    friend _LIBCPP_INLINE_VISIBILITY
4296        bool operator!=(const normal_distribution& __x,
4297                        const normal_distribution& __y)
4298        {return !(__x == __y);}
4299
4300    template <class _CharT, class _Traits, class _RT>
4301    friend
4302    basic_ostream<_CharT, _Traits>&
4303    operator<<(basic_ostream<_CharT, _Traits>& __os,
4304               const normal_distribution<_RT>& __x);
4305
4306    template <class _CharT, class _Traits, class _RT>
4307    friend
4308    basic_istream<_CharT, _Traits>&
4309    operator>>(basic_istream<_CharT, _Traits>& __is,
4310               normal_distribution<_RT>& __x);
4311};
4312
4313template <class _RealType>
4314template<class _URNG>
4315_RealType
4316normal_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
4317{
4318    result_type _Up;
4319    if (_V_hot_)
4320    {
4321        _V_hot_ = false;
4322        _Up = _V_;
4323    }
4324    else
4325    {
4326        uniform_real_distribution<result_type> _Uni(-1, 1);
4327        result_type __u;
4328        result_type __v;
4329        result_type __s;
4330        do
4331        {
4332            __u = _Uni(__g);
4333            __v = _Uni(__g);
4334            __s = __u * __u + __v * __v;
4335        } while (__s > 1 || __s == 0);
4336        result_type _Fp = _VSTD::sqrt(-2 * _VSTD::log(__s) / __s);
4337        _V_ = __v * _Fp;
4338        _V_hot_ = true;
4339        _Up = __u * _Fp;
4340    }
4341    return _Up * __p.stddev() + __p.mean();
4342}
4343
4344template <class _CharT, class _Traits, class _RT>
4345basic_ostream<_CharT, _Traits>&
4346operator<<(basic_ostream<_CharT, _Traits>& __os,
4347           const normal_distribution<_RT>& __x)
4348{
4349    __save_flags<_CharT, _Traits> __lx(__os);
4350    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
4351               ios_base::scientific);
4352    _CharT __sp = __os.widen(' ');
4353    __os.fill(__sp);
4354    __os << __x.mean() << __sp << __x.stddev() << __sp << __x._V_hot_;
4355    if (__x._V_hot_)
4356        __os << __sp << __x._V_;
4357    return __os;
4358}
4359
4360template <class _CharT, class _Traits, class _RT>
4361basic_istream<_CharT, _Traits>&
4362operator>>(basic_istream<_CharT, _Traits>& __is,
4363           normal_distribution<_RT>& __x)
4364{
4365    typedef normal_distribution<_RT> _Eng;
4366    typedef typename _Eng::result_type result_type;
4367    typedef typename _Eng::param_type param_type;
4368    __save_flags<_CharT, _Traits> __lx(__is);
4369    __is.flags(ios_base::dec | ios_base::skipws);
4370    result_type __mean;
4371    result_type __stddev;
4372    result_type _Vp = 0;
4373    bool _V_hot = false;
4374    __is >> __mean >> __stddev >> _V_hot;
4375    if (_V_hot)
4376        __is >> _Vp;
4377    if (!__is.fail())
4378    {
4379        __x.param(param_type(__mean, __stddev));
4380        __x._V_hot_ = _V_hot;
4381        __x._V_ = _Vp;
4382    }
4383    return __is;
4384}
4385
4386// lognormal_distribution
4387
4388template<class _RealType = double>
4389class _LIBCPP_TEMPLATE_VIS lognormal_distribution
4390{
4391public:
4392    // types
4393    typedef _RealType result_type;
4394
4395    class _LIBCPP_TEMPLATE_VIS param_type
4396    {
4397        normal_distribution<result_type> __nd_;
4398    public:
4399        typedef lognormal_distribution distribution_type;
4400
4401        _LIBCPP_INLINE_VISIBILITY
4402        explicit param_type(result_type __m = 0, result_type __s = 1)
4403            : __nd_(__m, __s) {}
4404
4405        _LIBCPP_INLINE_VISIBILITY
4406        result_type m() const {return __nd_.mean();}
4407        _LIBCPP_INLINE_VISIBILITY
4408        result_type s() const {return __nd_.stddev();}
4409
4410        friend _LIBCPP_INLINE_VISIBILITY
4411            bool operator==(const param_type& __x, const param_type& __y)
4412            {return __x.__nd_ == __y.__nd_;}
4413        friend _LIBCPP_INLINE_VISIBILITY
4414            bool operator!=(const param_type& __x, const param_type& __y)
4415            {return !(__x == __y);}
4416        friend class lognormal_distribution;
4417
4418        template <class _CharT, class _Traits, class _RT>
4419        friend
4420        basic_ostream<_CharT, _Traits>&
4421        operator<<(basic_ostream<_CharT, _Traits>& __os,
4422                   const lognormal_distribution<_RT>& __x);
4423
4424        template <class _CharT, class _Traits, class _RT>
4425        friend
4426        basic_istream<_CharT, _Traits>&
4427        operator>>(basic_istream<_CharT, _Traits>& __is,
4428                   lognormal_distribution<_RT>& __x);
4429    };
4430
4431private:
4432    param_type __p_;
4433
4434public:
4435    // constructor and reset functions
4436    _LIBCPP_INLINE_VISIBILITY
4437    explicit lognormal_distribution(result_type __m = 0, result_type __s = 1)
4438        : __p_(param_type(__m, __s)) {}
4439    _LIBCPP_INLINE_VISIBILITY
4440    explicit lognormal_distribution(const param_type& __p)
4441        : __p_(__p) {}
4442    _LIBCPP_INLINE_VISIBILITY
4443    void reset() {__p_.__nd_.reset();}
4444
4445    // generating functions
4446    template<class _URNG>
4447        _LIBCPP_INLINE_VISIBILITY
4448        result_type operator()(_URNG& __g)
4449        {return (*this)(__g, __p_);}
4450    template<class _URNG>
4451        _LIBCPP_INLINE_VISIBILITY
4452        result_type operator()(_URNG& __g, const param_type& __p)
4453        {return _VSTD::exp(const_cast<normal_distribution<result_type>&>(__p.__nd_)(__g));}
4454
4455    // property functions
4456    _LIBCPP_INLINE_VISIBILITY
4457    result_type m() const {return __p_.m();}
4458    _LIBCPP_INLINE_VISIBILITY
4459    result_type s() const {return __p_.s();}
4460
4461    _LIBCPP_INLINE_VISIBILITY
4462    param_type param() const {return __p_;}
4463    _LIBCPP_INLINE_VISIBILITY
4464    void param(const param_type& __p) {__p_ = __p;}
4465
4466    _LIBCPP_INLINE_VISIBILITY
4467    result_type min() const {return 0;}
4468    _LIBCPP_INLINE_VISIBILITY
4469    result_type max() const {return numeric_limits<result_type>::infinity();}
4470
4471    friend _LIBCPP_INLINE_VISIBILITY
4472        bool operator==(const lognormal_distribution& __x,
4473                        const lognormal_distribution& __y)
4474        {return __x.__p_ == __y.__p_;}
4475    friend _LIBCPP_INLINE_VISIBILITY
4476        bool operator!=(const lognormal_distribution& __x,
4477                        const lognormal_distribution& __y)
4478        {return !(__x == __y);}
4479
4480    template <class _CharT, class _Traits, class _RT>
4481    friend
4482    basic_ostream<_CharT, _Traits>&
4483    operator<<(basic_ostream<_CharT, _Traits>& __os,
4484               const lognormal_distribution<_RT>& __x);
4485
4486    template <class _CharT, class _Traits, class _RT>
4487    friend
4488    basic_istream<_CharT, _Traits>&
4489    operator>>(basic_istream<_CharT, _Traits>& __is,
4490               lognormal_distribution<_RT>& __x);
4491};
4492
4493template <class _CharT, class _Traits, class _RT>
4494inline _LIBCPP_INLINE_VISIBILITY
4495basic_ostream<_CharT, _Traits>&
4496operator<<(basic_ostream<_CharT, _Traits>& __os,
4497           const lognormal_distribution<_RT>& __x)
4498{
4499    return __os << __x.__p_.__nd_;
4500}
4501
4502template <class _CharT, class _Traits, class _RT>
4503inline _LIBCPP_INLINE_VISIBILITY
4504basic_istream<_CharT, _Traits>&
4505operator>>(basic_istream<_CharT, _Traits>& __is,
4506           lognormal_distribution<_RT>& __x)
4507{
4508    return __is >> __x.__p_.__nd_;
4509}
4510
4511// poisson_distribution
4512
4513template<class _IntType = int>
4514class _LIBCPP_TEMPLATE_VIS poisson_distribution
4515{
4516public:
4517    // types
4518    typedef _IntType result_type;
4519
4520    class _LIBCPP_TEMPLATE_VIS param_type
4521    {
4522        double __mean_;
4523        double __s_;
4524        double __d_;
4525        double __l_;
4526        double __omega_;
4527        double __c0_;
4528        double __c1_;
4529        double __c2_;
4530        double __c3_;
4531        double __c_;
4532
4533    public:
4534        typedef poisson_distribution distribution_type;
4535
4536        explicit param_type(double __mean = 1.0);
4537
4538        _LIBCPP_INLINE_VISIBILITY
4539        double mean() const {return __mean_;}
4540
4541        friend _LIBCPP_INLINE_VISIBILITY
4542            bool operator==(const param_type& __x, const param_type& __y)
4543            {return __x.__mean_ == __y.__mean_;}
4544        friend _LIBCPP_INLINE_VISIBILITY
4545            bool operator!=(const param_type& __x, const param_type& __y)
4546            {return !(__x == __y);}
4547
4548        friend class poisson_distribution;
4549    };
4550
4551private:
4552    param_type __p_;
4553
4554public:
4555    // constructors and reset functions
4556    _LIBCPP_INLINE_VISIBILITY
4557    explicit poisson_distribution(double __mean = 1.0) : __p_(__mean) {}
4558    _LIBCPP_INLINE_VISIBILITY
4559    explicit poisson_distribution(const param_type& __p) : __p_(__p) {}
4560    _LIBCPP_INLINE_VISIBILITY
4561    void reset() {}
4562
4563    // generating functions
4564    template<class _URNG>
4565        _LIBCPP_INLINE_VISIBILITY
4566        result_type operator()(_URNG& __g)
4567        {return (*this)(__g, __p_);}
4568    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
4569
4570    // property functions
4571    _LIBCPP_INLINE_VISIBILITY
4572    double mean() const {return __p_.mean();}
4573
4574    _LIBCPP_INLINE_VISIBILITY
4575    param_type param() const {return __p_;}
4576    _LIBCPP_INLINE_VISIBILITY
4577    void param(const param_type& __p) {__p_ = __p;}
4578
4579    _LIBCPP_INLINE_VISIBILITY
4580    result_type min() const {return 0;}
4581    _LIBCPP_INLINE_VISIBILITY
4582    result_type max() const {return numeric_limits<result_type>::max();}
4583
4584    friend _LIBCPP_INLINE_VISIBILITY
4585        bool operator==(const poisson_distribution& __x,
4586                        const poisson_distribution& __y)
4587        {return __x.__p_ == __y.__p_;}
4588    friend _LIBCPP_INLINE_VISIBILITY
4589        bool operator!=(const poisson_distribution& __x,
4590                        const poisson_distribution& __y)
4591        {return !(__x == __y);}
4592};
4593
4594template<class _IntType>
4595poisson_distribution<_IntType>::param_type::param_type(double __mean)
4596    // According to the standard `inf` is a valid input, but it causes the
4597    // distribution to hang, so we replace it with the maximum representable
4598    // mean.
4599    : __mean_(isinf(__mean) ? numeric_limits<double>::max() : __mean)
4600{
4601    if (__mean_ < 10)
4602    {
4603        __s_ = 0;
4604        __d_ = 0;
4605        __l_ = _VSTD::exp(-__mean_);
4606        __omega_ = 0;
4607        __c3_ = 0;
4608        __c2_ = 0;
4609        __c1_ = 0;
4610        __c0_ = 0;
4611        __c_ = 0;
4612    }
4613    else
4614    {
4615        __s_ = _VSTD::sqrt(__mean_);
4616        __d_ = 6 * __mean_ * __mean_;
4617        __l_ = std::trunc(__mean_ - 1.1484);
4618        __omega_ = .3989423 / __s_;
4619        double __b1_ = .4166667E-1 / __mean_;
4620        double __b2_ = .3 * __b1_ * __b1_;
4621        __c3_ = .1428571 * __b1_ * __b2_;
4622        __c2_ = __b2_ - 15. * __c3_;
4623        __c1_ = __b1_ - 6. * __b2_ + 45. * __c3_;
4624        __c0_ = 1. - __b1_ + 3. * __b2_ - 15. * __c3_;
4625        __c_ = .1069 / __mean_;
4626    }
4627}
4628
4629template <class _IntType>
4630template<class _URNG>
4631_IntType
4632poisson_distribution<_IntType>::operator()(_URNG& __urng, const param_type& __pr)
4633{
4634    double __tx;
4635    uniform_real_distribution<double> __urd;
4636    if (__pr.__mean_ < 10)
4637    {
4638         __tx = 0;
4639        for (double __p = __urd(__urng); __p > __pr.__l_; ++__tx)
4640            __p *= __urd(__urng);
4641    }
4642    else
4643    {
4644        double __difmuk;
4645        double __g = __pr.__mean_ + __pr.__s_ * normal_distribution<double>()(__urng);
4646        double __u;
4647        if (__g > 0)
4648        {
4649            __tx = std::trunc(__g);
4650            if (__tx >= __pr.__l_)
4651                return std::__clamp_to_integral<result_type>(__tx);
4652            __difmuk = __pr.__mean_ - __tx;
4653            __u = __urd(__urng);
4654            if (__pr.__d_ * __u >= __difmuk * __difmuk * __difmuk)
4655                return std::__clamp_to_integral<result_type>(__tx);
4656        }
4657        exponential_distribution<double> __edist;
4658        for (bool __using_exp_dist = false; true; __using_exp_dist = true)
4659        {
4660            double __e;
4661            if (__using_exp_dist || __g <= 0)
4662            {
4663                double __t;
4664                do
4665                {
4666                    __e = __edist(__urng);
4667                    __u = __urd(__urng);
4668                    __u += __u - 1;
4669                    __t = 1.8 + (__u < 0 ? -__e : __e);
4670                } while (__t <= -.6744);
4671                __tx = std::trunc(__pr.__mean_ + __pr.__s_ * __t);
4672                __difmuk = __pr.__mean_ - __tx;
4673                __using_exp_dist = true;
4674            }
4675            double __px;
4676            double __py;
4677            if (__tx < 10 && __tx >= 0)
4678            {
4679                const double __fac[] = {1, 1, 2, 6, 24, 120, 720, 5040,
4680                                             40320, 362880};
4681                __px = -__pr.__mean_;
4682                __py = _VSTD::pow(__pr.__mean_, (double)__tx) / __fac[static_cast<int>(__tx)];
4683            }
4684            else
4685            {
4686                double __del = .8333333E-1 / __tx;
4687                __del -= 4.8 * __del * __del * __del;
4688                double __v = __difmuk / __tx;
4689                if (_VSTD::abs(__v) > 0.25)
4690                    __px = __tx * _VSTD::log(1 + __v) - __difmuk - __del;
4691                else
4692                    __px = __tx * __v * __v * (((((((.1250060 * __v + -.1384794) *
4693                           __v + .1421878) * __v + -.1661269) * __v + .2000118) *
4694                           __v + -.2500068) * __v + .3333333) * __v + -.5) - __del;
4695                __py = .3989423 / _VSTD::sqrt(__tx);
4696            }
4697            double __r = (0.5 - __difmuk) / __pr.__s_;
4698            double __r2 = __r * __r;
4699            double __fx = -0.5 * __r2;
4700            double __fy = __pr.__omega_ * (((__pr.__c3_ * __r2 + __pr.__c2_) *
4701                                        __r2 + __pr.__c1_) * __r2 + __pr.__c0_);
4702            if (__using_exp_dist)
4703            {
4704                if (__pr.__c_ * _VSTD::abs(__u) <= __py * _VSTD::exp(__px + __e) -
4705                                                   __fy * _VSTD::exp(__fx + __e))
4706                    break;
4707            }
4708            else
4709            {
4710                if (__fy - __u * __fy <= __py * _VSTD::exp(__px - __fx))
4711                    break;
4712            }
4713        }
4714    }
4715    return std::__clamp_to_integral<result_type>(__tx);
4716}
4717
4718template <class _CharT, class _Traits, class _IntType>
4719basic_ostream<_CharT, _Traits>&
4720operator<<(basic_ostream<_CharT, _Traits>& __os,
4721           const poisson_distribution<_IntType>& __x)
4722{
4723    __save_flags<_CharT, _Traits> __lx(__os);
4724    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
4725               ios_base::scientific);
4726    return __os << __x.mean();
4727}
4728
4729template <class _CharT, class _Traits, class _IntType>
4730basic_istream<_CharT, _Traits>&
4731operator>>(basic_istream<_CharT, _Traits>& __is,
4732           poisson_distribution<_IntType>& __x)
4733{
4734    typedef poisson_distribution<_IntType> _Eng;
4735    typedef typename _Eng::param_type param_type;
4736    __save_flags<_CharT, _Traits> __lx(__is);
4737    __is.flags(ios_base::dec | ios_base::skipws);
4738    double __mean;
4739    __is >> __mean;
4740    if (!__is.fail())
4741        __x.param(param_type(__mean));
4742    return __is;
4743}
4744
4745// weibull_distribution
4746
4747template<class _RealType = double>
4748class _LIBCPP_TEMPLATE_VIS weibull_distribution
4749{
4750public:
4751    // types
4752    typedef _RealType result_type;
4753
4754    class _LIBCPP_TEMPLATE_VIS param_type
4755    {
4756        result_type __a_;
4757        result_type __b_;
4758    public:
4759        typedef weibull_distribution distribution_type;
4760
4761        _LIBCPP_INLINE_VISIBILITY
4762        explicit param_type(result_type __a = 1, result_type __b = 1)
4763            : __a_(__a), __b_(__b) {}
4764
4765        _LIBCPP_INLINE_VISIBILITY
4766        result_type a() const {return __a_;}
4767        _LIBCPP_INLINE_VISIBILITY
4768        result_type b() const {return __b_;}
4769
4770        friend _LIBCPP_INLINE_VISIBILITY
4771            bool operator==(const param_type& __x, const param_type& __y)
4772            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
4773        friend _LIBCPP_INLINE_VISIBILITY
4774            bool operator!=(const param_type& __x, const param_type& __y)
4775            {return !(__x == __y);}
4776    };
4777
4778private:
4779    param_type __p_;
4780
4781public:
4782    // constructor and reset functions
4783    _LIBCPP_INLINE_VISIBILITY
4784    explicit weibull_distribution(result_type __a = 1, result_type __b = 1)
4785        : __p_(param_type(__a, __b)) {}
4786    _LIBCPP_INLINE_VISIBILITY
4787    explicit weibull_distribution(const param_type& __p)
4788        : __p_(__p) {}
4789    _LIBCPP_INLINE_VISIBILITY
4790    void reset() {}
4791
4792    // generating functions
4793    template<class _URNG>
4794        _LIBCPP_INLINE_VISIBILITY
4795        result_type operator()(_URNG& __g)
4796        {return (*this)(__g, __p_);}
4797    template<class _URNG>
4798        _LIBCPP_INLINE_VISIBILITY
4799        result_type operator()(_URNG& __g, const param_type& __p)
4800        {return __p.b() *
4801            _VSTD::pow(exponential_distribution<result_type>()(__g), 1/__p.a());}
4802
4803    // property functions
4804    _LIBCPP_INLINE_VISIBILITY
4805    result_type a() const {return __p_.a();}
4806    _LIBCPP_INLINE_VISIBILITY
4807    result_type b() const {return __p_.b();}
4808
4809    _LIBCPP_INLINE_VISIBILITY
4810    param_type param() const {return __p_;}
4811    _LIBCPP_INLINE_VISIBILITY
4812    void param(const param_type& __p) {__p_ = __p;}
4813
4814    _LIBCPP_INLINE_VISIBILITY
4815    result_type min() const {return 0;}
4816    _LIBCPP_INLINE_VISIBILITY
4817    result_type max() const {return numeric_limits<result_type>::infinity();}
4818
4819    friend _LIBCPP_INLINE_VISIBILITY
4820        bool operator==(const weibull_distribution& __x,
4821                        const weibull_distribution& __y)
4822        {return __x.__p_ == __y.__p_;}
4823    friend _LIBCPP_INLINE_VISIBILITY
4824        bool operator!=(const weibull_distribution& __x,
4825                        const weibull_distribution& __y)
4826        {return !(__x == __y);}
4827};
4828
4829template <class _CharT, class _Traits, class _RT>
4830basic_ostream<_CharT, _Traits>&
4831operator<<(basic_ostream<_CharT, _Traits>& __os,
4832           const weibull_distribution<_RT>& __x)
4833{
4834    __save_flags<_CharT, _Traits> __lx(__os);
4835    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
4836               ios_base::scientific);
4837    _CharT __sp = __os.widen(' ');
4838    __os.fill(__sp);
4839    __os << __x.a() << __sp << __x.b();
4840    return __os;
4841}
4842
4843template <class _CharT, class _Traits, class _RT>
4844basic_istream<_CharT, _Traits>&
4845operator>>(basic_istream<_CharT, _Traits>& __is,
4846           weibull_distribution<_RT>& __x)
4847{
4848    typedef weibull_distribution<_RT> _Eng;
4849    typedef typename _Eng::result_type result_type;
4850    typedef typename _Eng::param_type param_type;
4851    __save_flags<_CharT, _Traits> __lx(__is);
4852    __is.flags(ios_base::dec | ios_base::skipws);
4853    result_type __a;
4854    result_type __b;
4855    __is >> __a >> __b;
4856    if (!__is.fail())
4857        __x.param(param_type(__a, __b));
4858    return __is;
4859}
4860
4861template<class _RealType = double>
4862class _LIBCPP_TEMPLATE_VIS extreme_value_distribution
4863{
4864public:
4865    // types
4866    typedef _RealType result_type;
4867
4868    class _LIBCPP_TEMPLATE_VIS param_type
4869    {
4870        result_type __a_;
4871        result_type __b_;
4872    public:
4873        typedef extreme_value_distribution distribution_type;
4874
4875        _LIBCPP_INLINE_VISIBILITY
4876        explicit param_type(result_type __a = 0, result_type __b = 1)
4877            : __a_(__a), __b_(__b) {}
4878
4879        _LIBCPP_INLINE_VISIBILITY
4880        result_type a() const {return __a_;}
4881        _LIBCPP_INLINE_VISIBILITY
4882        result_type b() const {return __b_;}
4883
4884        friend _LIBCPP_INLINE_VISIBILITY
4885            bool operator==(const param_type& __x, const param_type& __y)
4886            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
4887        friend _LIBCPP_INLINE_VISIBILITY
4888            bool operator!=(const param_type& __x, const param_type& __y)
4889            {return !(__x == __y);}
4890    };
4891
4892private:
4893    param_type __p_;
4894
4895public:
4896    // constructor and reset functions
4897    _LIBCPP_INLINE_VISIBILITY
4898    explicit extreme_value_distribution(result_type __a = 0, result_type __b = 1)
4899        : __p_(param_type(__a, __b)) {}
4900    _LIBCPP_INLINE_VISIBILITY
4901    explicit extreme_value_distribution(const param_type& __p)
4902        : __p_(__p) {}
4903    _LIBCPP_INLINE_VISIBILITY
4904    void reset() {}
4905
4906    // generating functions
4907    template<class _URNG>
4908        _LIBCPP_INLINE_VISIBILITY
4909        result_type operator()(_URNG& __g)
4910        {return (*this)(__g, __p_);}
4911    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
4912
4913    // property functions
4914    _LIBCPP_INLINE_VISIBILITY
4915    result_type a() const {return __p_.a();}
4916    _LIBCPP_INLINE_VISIBILITY
4917    result_type b() const {return __p_.b();}
4918
4919    _LIBCPP_INLINE_VISIBILITY
4920    param_type param() const {return __p_;}
4921    _LIBCPP_INLINE_VISIBILITY
4922    void param(const param_type& __p) {__p_ = __p;}
4923
4924    _LIBCPP_INLINE_VISIBILITY
4925    result_type min() const {return -numeric_limits<result_type>::infinity();}
4926    _LIBCPP_INLINE_VISIBILITY
4927    result_type max() const {return numeric_limits<result_type>::infinity();}
4928
4929    friend _LIBCPP_INLINE_VISIBILITY
4930        bool operator==(const extreme_value_distribution& __x,
4931                        const extreme_value_distribution& __y)
4932        {return __x.__p_ == __y.__p_;}
4933    friend _LIBCPP_INLINE_VISIBILITY
4934        bool operator!=(const extreme_value_distribution& __x,
4935                        const extreme_value_distribution& __y)
4936        {return !(__x == __y);}
4937};
4938
4939template<class _RealType>
4940template<class _URNG>
4941_RealType
4942extreme_value_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
4943{
4944    return __p.a() - __p.b() *
4945         _VSTD::log(-_VSTD::log(1-uniform_real_distribution<result_type>()(__g)));
4946}
4947
4948template <class _CharT, class _Traits, class _RT>
4949basic_ostream<_CharT, _Traits>&
4950operator<<(basic_ostream<_CharT, _Traits>& __os,
4951           const extreme_value_distribution<_RT>& __x)
4952{
4953    __save_flags<_CharT, _Traits> __lx(__os);
4954    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
4955               ios_base::scientific);
4956    _CharT __sp = __os.widen(' ');
4957    __os.fill(__sp);
4958    __os << __x.a() << __sp << __x.b();
4959    return __os;
4960}
4961
4962template <class _CharT, class _Traits, class _RT>
4963basic_istream<_CharT, _Traits>&
4964operator>>(basic_istream<_CharT, _Traits>& __is,
4965           extreme_value_distribution<_RT>& __x)
4966{
4967    typedef extreme_value_distribution<_RT> _Eng;
4968    typedef typename _Eng::result_type result_type;
4969    typedef typename _Eng::param_type param_type;
4970    __save_flags<_CharT, _Traits> __lx(__is);
4971    __is.flags(ios_base::dec | ios_base::skipws);
4972    result_type __a;
4973    result_type __b;
4974    __is >> __a >> __b;
4975    if (!__is.fail())
4976        __x.param(param_type(__a, __b));
4977    return __is;
4978}
4979
4980// gamma_distribution
4981
4982template<class _RealType = double>
4983class _LIBCPP_TEMPLATE_VIS gamma_distribution
4984{
4985public:
4986    // types
4987    typedef _RealType result_type;
4988
4989    class _LIBCPP_TEMPLATE_VIS param_type
4990    {
4991        result_type __alpha_;
4992        result_type __beta_;
4993    public:
4994        typedef gamma_distribution distribution_type;
4995
4996        _LIBCPP_INLINE_VISIBILITY
4997        explicit param_type(result_type __alpha = 1, result_type __beta = 1)
4998            : __alpha_(__alpha), __beta_(__beta) {}
4999
5000        _LIBCPP_INLINE_VISIBILITY
5001        result_type alpha() const {return __alpha_;}
5002        _LIBCPP_INLINE_VISIBILITY
5003        result_type beta() const {return __beta_;}
5004
5005        friend _LIBCPP_INLINE_VISIBILITY
5006            bool operator==(const param_type& __x, const param_type& __y)
5007            {return __x.__alpha_ == __y.__alpha_ && __x.__beta_ == __y.__beta_;}
5008        friend _LIBCPP_INLINE_VISIBILITY
5009            bool operator!=(const param_type& __x, const param_type& __y)
5010            {return !(__x == __y);}
5011    };
5012
5013private:
5014    param_type __p_;
5015
5016public:
5017    // constructors and reset functions
5018    _LIBCPP_INLINE_VISIBILITY
5019    explicit gamma_distribution(result_type __alpha = 1, result_type __beta = 1)
5020        : __p_(param_type(__alpha, __beta)) {}
5021    _LIBCPP_INLINE_VISIBILITY
5022    explicit gamma_distribution(const param_type& __p)
5023        : __p_(__p) {}
5024    _LIBCPP_INLINE_VISIBILITY
5025    void reset() {}
5026
5027    // generating functions
5028    template<class _URNG>
5029        _LIBCPP_INLINE_VISIBILITY
5030        result_type operator()(_URNG& __g)
5031        {return (*this)(__g, __p_);}
5032    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
5033
5034    // property functions
5035    _LIBCPP_INLINE_VISIBILITY
5036    result_type alpha() const {return __p_.alpha();}
5037    _LIBCPP_INLINE_VISIBILITY
5038    result_type beta() const {return __p_.beta();}
5039
5040    _LIBCPP_INLINE_VISIBILITY
5041    param_type param() const {return __p_;}
5042    _LIBCPP_INLINE_VISIBILITY
5043    void param(const param_type& __p) {__p_ = __p;}
5044
5045    _LIBCPP_INLINE_VISIBILITY
5046    result_type min() const {return 0;}
5047    _LIBCPP_INLINE_VISIBILITY
5048    result_type max() const {return numeric_limits<result_type>::infinity();}
5049
5050    friend _LIBCPP_INLINE_VISIBILITY
5051        bool operator==(const gamma_distribution& __x,
5052                        const gamma_distribution& __y)
5053        {return __x.__p_ == __y.__p_;}
5054    friend _LIBCPP_INLINE_VISIBILITY
5055        bool operator!=(const gamma_distribution& __x,
5056                        const gamma_distribution& __y)
5057        {return !(__x == __y);}
5058};
5059
5060template <class _RealType>
5061template<class _URNG>
5062_RealType
5063gamma_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
5064{
5065    result_type __a = __p.alpha();
5066    uniform_real_distribution<result_type> __gen(0, 1);
5067    exponential_distribution<result_type> __egen;
5068    result_type __x;
5069    if (__a == 1)
5070        __x = __egen(__g);
5071    else if (__a > 1)
5072    {
5073        const result_type __b = __a - 1;
5074        const result_type __c = 3 * __a - result_type(0.75);
5075        while (true)
5076        {
5077            const result_type __u = __gen(__g);
5078            const result_type __v = __gen(__g);
5079            const result_type __w = __u * (1 - __u);
5080            if (__w != 0)
5081            {
5082                const result_type __y = _VSTD::sqrt(__c / __w) *
5083                                        (__u - result_type(0.5));
5084                __x = __b + __y;
5085                if (__x >= 0)
5086                {
5087                    const result_type __z = 64 * __w * __w * __w * __v * __v;
5088                    if (__z <= 1 - 2 * __y * __y / __x)
5089                        break;
5090                    if (_VSTD::log(__z) <= 2 * (__b * _VSTD::log(__x / __b) - __y))
5091                        break;
5092                }
5093            }
5094        }
5095    }
5096    else  // __a < 1
5097    {
5098        while (true)
5099        {
5100            const result_type __u = __gen(__g);
5101            const result_type __es = __egen(__g);
5102            if (__u <= 1 - __a)
5103            {
5104                __x = _VSTD::pow(__u, 1 / __a);
5105                if (__x <= __es)
5106                    break;
5107            }
5108            else
5109            {
5110                const result_type __e = -_VSTD::log((1-__u)/__a);
5111                __x = _VSTD::pow(1 - __a + __a * __e, 1 / __a);
5112                if (__x <= __e + __es)
5113                    break;
5114            }
5115        }
5116    }
5117    return __x * __p.beta();
5118}
5119
5120template <class _CharT, class _Traits, class _RT>
5121basic_ostream<_CharT, _Traits>&
5122operator<<(basic_ostream<_CharT, _Traits>& __os,
5123           const gamma_distribution<_RT>& __x)
5124{
5125    __save_flags<_CharT, _Traits> __lx(__os);
5126    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5127               ios_base::scientific);
5128    _CharT __sp = __os.widen(' ');
5129    __os.fill(__sp);
5130    __os << __x.alpha() << __sp << __x.beta();
5131    return __os;
5132}
5133
5134template <class _CharT, class _Traits, class _RT>
5135basic_istream<_CharT, _Traits>&
5136operator>>(basic_istream<_CharT, _Traits>& __is,
5137           gamma_distribution<_RT>& __x)
5138{
5139    typedef gamma_distribution<_RT> _Eng;
5140    typedef typename _Eng::result_type result_type;
5141    typedef typename _Eng::param_type param_type;
5142    __save_flags<_CharT, _Traits> __lx(__is);
5143    __is.flags(ios_base::dec | ios_base::skipws);
5144    result_type __alpha;
5145    result_type __beta;
5146    __is >> __alpha >> __beta;
5147    if (!__is.fail())
5148        __x.param(param_type(__alpha, __beta));
5149    return __is;
5150}
5151
5152// negative_binomial_distribution
5153
5154template<class _IntType = int>
5155class _LIBCPP_TEMPLATE_VIS negative_binomial_distribution
5156{
5157public:
5158    // types
5159    typedef _IntType result_type;
5160
5161    class _LIBCPP_TEMPLATE_VIS param_type
5162    {
5163        result_type __k_;
5164        double __p_;
5165    public:
5166        typedef negative_binomial_distribution distribution_type;
5167
5168        _LIBCPP_INLINE_VISIBILITY
5169        explicit param_type(result_type __k = 1, double __p = 0.5)
5170            : __k_(__k), __p_(__p) {}
5171
5172        _LIBCPP_INLINE_VISIBILITY
5173        result_type k() const {return __k_;}
5174        _LIBCPP_INLINE_VISIBILITY
5175        double p() const {return __p_;}
5176
5177        friend _LIBCPP_INLINE_VISIBILITY
5178            bool operator==(const param_type& __x, const param_type& __y)
5179            {return __x.__k_ == __y.__k_ && __x.__p_ == __y.__p_;}
5180        friend _LIBCPP_INLINE_VISIBILITY
5181            bool operator!=(const param_type& __x, const param_type& __y)
5182            {return !(__x == __y);}
5183    };
5184
5185private:
5186    param_type __p_;
5187
5188public:
5189    // constructor and reset functions
5190    _LIBCPP_INLINE_VISIBILITY
5191    explicit negative_binomial_distribution(result_type __k = 1, double __p = 0.5)
5192        : __p_(__k, __p) {}
5193    _LIBCPP_INLINE_VISIBILITY
5194    explicit negative_binomial_distribution(const param_type& __p) : __p_(__p) {}
5195    _LIBCPP_INLINE_VISIBILITY
5196    void reset() {}
5197
5198    // generating functions
5199    template<class _URNG>
5200        _LIBCPP_INLINE_VISIBILITY
5201        result_type operator()(_URNG& __g)
5202        {return (*this)(__g, __p_);}
5203    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
5204
5205    // property functions
5206    _LIBCPP_INLINE_VISIBILITY
5207    result_type k() const {return __p_.k();}
5208    _LIBCPP_INLINE_VISIBILITY
5209    double p() const {return __p_.p();}
5210
5211    _LIBCPP_INLINE_VISIBILITY
5212    param_type param() const {return __p_;}
5213    _LIBCPP_INLINE_VISIBILITY
5214    void param(const param_type& __p) {__p_ = __p;}
5215
5216    _LIBCPP_INLINE_VISIBILITY
5217    result_type min() const {return 0;}
5218    _LIBCPP_INLINE_VISIBILITY
5219    result_type max() const {return numeric_limits<result_type>::max();}
5220
5221    friend _LIBCPP_INLINE_VISIBILITY
5222        bool operator==(const negative_binomial_distribution& __x,
5223                        const negative_binomial_distribution& __y)
5224        {return __x.__p_ == __y.__p_;}
5225    friend _LIBCPP_INLINE_VISIBILITY
5226        bool operator!=(const negative_binomial_distribution& __x,
5227                        const negative_binomial_distribution& __y)
5228        {return !(__x == __y);}
5229};
5230
5231template <class _IntType>
5232template<class _URNG>
5233_IntType
5234negative_binomial_distribution<_IntType>::operator()(_URNG& __urng, const param_type& __pr)
5235{
5236    result_type __k = __pr.k();
5237    double __p = __pr.p();
5238    if (__k <= 21 * __p)
5239    {
5240        bernoulli_distribution __gen(__p);
5241        result_type __f = 0;
5242        result_type __s = 0;
5243        while (__s < __k)
5244        {
5245            if (__gen(__urng))
5246                ++__s;
5247            else
5248                ++__f;
5249        }
5250        return __f;
5251    }
5252    return poisson_distribution<result_type>(gamma_distribution<double>
5253                                            (__k, (1-__p)/__p)(__urng))(__urng);
5254}
5255
5256template <class _CharT, class _Traits, class _IntType>
5257basic_ostream<_CharT, _Traits>&
5258operator<<(basic_ostream<_CharT, _Traits>& __os,
5259           const negative_binomial_distribution<_IntType>& __x)
5260{
5261    __save_flags<_CharT, _Traits> __lx(__os);
5262    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5263               ios_base::scientific);
5264    _CharT __sp = __os.widen(' ');
5265    __os.fill(__sp);
5266    return __os << __x.k() << __sp << __x.p();
5267}
5268
5269template <class _CharT, class _Traits, class _IntType>
5270basic_istream<_CharT, _Traits>&
5271operator>>(basic_istream<_CharT, _Traits>& __is,
5272           negative_binomial_distribution<_IntType>& __x)
5273{
5274    typedef negative_binomial_distribution<_IntType> _Eng;
5275    typedef typename _Eng::result_type result_type;
5276    typedef typename _Eng::param_type param_type;
5277    __save_flags<_CharT, _Traits> __lx(__is);
5278    __is.flags(ios_base::dec | ios_base::skipws);
5279    result_type __k;
5280    double __p;
5281    __is >> __k >> __p;
5282    if (!__is.fail())
5283        __x.param(param_type(__k, __p));
5284    return __is;
5285}
5286
5287// geometric_distribution
5288
5289template<class _IntType = int>
5290class _LIBCPP_TEMPLATE_VIS geometric_distribution
5291{
5292public:
5293    // types
5294    typedef _IntType result_type;
5295
5296    class _LIBCPP_TEMPLATE_VIS param_type
5297    {
5298        double __p_;
5299    public:
5300        typedef geometric_distribution distribution_type;
5301
5302        _LIBCPP_INLINE_VISIBILITY
5303        explicit param_type(double __p = 0.5) : __p_(__p) {}
5304
5305        _LIBCPP_INLINE_VISIBILITY
5306        double p() const {return __p_;}
5307
5308        friend _LIBCPP_INLINE_VISIBILITY
5309            bool operator==(const param_type& __x, const param_type& __y)
5310            {return __x.__p_ == __y.__p_;}
5311        friend _LIBCPP_INLINE_VISIBILITY
5312            bool operator!=(const param_type& __x, const param_type& __y)
5313            {return !(__x == __y);}
5314    };
5315
5316private:
5317    param_type __p_;
5318
5319public:
5320    // constructors and reset functions
5321    _LIBCPP_INLINE_VISIBILITY
5322    explicit geometric_distribution(double __p = 0.5) : __p_(__p) {}
5323    _LIBCPP_INLINE_VISIBILITY
5324    explicit geometric_distribution(const param_type& __p) : __p_(__p) {}
5325    _LIBCPP_INLINE_VISIBILITY
5326    void reset() {}
5327
5328    // generating functions
5329    template<class _URNG>
5330        _LIBCPP_INLINE_VISIBILITY
5331        result_type operator()(_URNG& __g)
5332        {return (*this)(__g, __p_);}
5333    template<class _URNG>
5334        _LIBCPP_INLINE_VISIBILITY
5335        result_type operator()(_URNG& __g, const param_type& __p)
5336        {return negative_binomial_distribution<result_type>(1, __p.p())(__g);}
5337
5338    // property functions
5339    _LIBCPP_INLINE_VISIBILITY
5340    double p() const {return __p_.p();}
5341
5342    _LIBCPP_INLINE_VISIBILITY
5343    param_type param() const {return __p_;}
5344    _LIBCPP_INLINE_VISIBILITY
5345    void param(const param_type& __p) {__p_ = __p;}
5346
5347    _LIBCPP_INLINE_VISIBILITY
5348    result_type min() const {return 0;}
5349    _LIBCPP_INLINE_VISIBILITY
5350    result_type max() const {return numeric_limits<result_type>::max();}
5351
5352    friend _LIBCPP_INLINE_VISIBILITY
5353        bool operator==(const geometric_distribution& __x,
5354                        const geometric_distribution& __y)
5355        {return __x.__p_ == __y.__p_;}
5356    friend _LIBCPP_INLINE_VISIBILITY
5357        bool operator!=(const geometric_distribution& __x,
5358                        const geometric_distribution& __y)
5359        {return !(__x == __y);}
5360};
5361
5362template <class _CharT, class _Traits, class _IntType>
5363basic_ostream<_CharT, _Traits>&
5364operator<<(basic_ostream<_CharT, _Traits>& __os,
5365           const geometric_distribution<_IntType>& __x)
5366{
5367    __save_flags<_CharT, _Traits> __lx(__os);
5368    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5369               ios_base::scientific);
5370    return __os << __x.p();
5371}
5372
5373template <class _CharT, class _Traits, class _IntType>
5374basic_istream<_CharT, _Traits>&
5375operator>>(basic_istream<_CharT, _Traits>& __is,
5376           geometric_distribution<_IntType>& __x)
5377{
5378    typedef geometric_distribution<_IntType> _Eng;
5379    typedef typename _Eng::param_type param_type;
5380    __save_flags<_CharT, _Traits> __lx(__is);
5381    __is.flags(ios_base::dec | ios_base::skipws);
5382    double __p;
5383    __is >> __p;
5384    if (!__is.fail())
5385        __x.param(param_type(__p));
5386    return __is;
5387}
5388
5389// chi_squared_distribution
5390
5391template<class _RealType = double>
5392class _LIBCPP_TEMPLATE_VIS chi_squared_distribution
5393{
5394public:
5395    // types
5396    typedef _RealType result_type;
5397
5398    class _LIBCPP_TEMPLATE_VIS param_type
5399    {
5400        result_type __n_;
5401    public:
5402        typedef chi_squared_distribution distribution_type;
5403
5404        _LIBCPP_INLINE_VISIBILITY
5405        explicit param_type(result_type __n = 1) : __n_(__n) {}
5406
5407        _LIBCPP_INLINE_VISIBILITY
5408        result_type n() const {return __n_;}
5409
5410        friend _LIBCPP_INLINE_VISIBILITY
5411            bool operator==(const param_type& __x, const param_type& __y)
5412            {return __x.__n_ == __y.__n_;}
5413        friend _LIBCPP_INLINE_VISIBILITY
5414            bool operator!=(const param_type& __x, const param_type& __y)
5415            {return !(__x == __y);}
5416    };
5417
5418private:
5419    param_type __p_;
5420
5421public:
5422    // constructor and reset functions
5423    _LIBCPP_INLINE_VISIBILITY
5424    explicit chi_squared_distribution(result_type __n = 1)
5425        : __p_(param_type(__n)) {}
5426    _LIBCPP_INLINE_VISIBILITY
5427    explicit chi_squared_distribution(const param_type& __p)
5428        : __p_(__p) {}
5429    _LIBCPP_INLINE_VISIBILITY
5430    void reset() {}
5431
5432    // generating functions
5433    template<class _URNG>
5434        _LIBCPP_INLINE_VISIBILITY
5435        result_type operator()(_URNG& __g)
5436        {return (*this)(__g, __p_);}
5437    template<class _URNG>
5438        _LIBCPP_INLINE_VISIBILITY
5439        result_type operator()(_URNG& __g, const param_type& __p)
5440        {return gamma_distribution<result_type>(__p.n() / 2, 2)(__g);}
5441
5442    // property functions
5443    _LIBCPP_INLINE_VISIBILITY
5444    result_type n() const {return __p_.n();}
5445
5446    _LIBCPP_INLINE_VISIBILITY
5447    param_type param() const {return __p_;}
5448    _LIBCPP_INLINE_VISIBILITY
5449    void param(const param_type& __p) {__p_ = __p;}
5450
5451    _LIBCPP_INLINE_VISIBILITY
5452    result_type min() const {return 0;}
5453    _LIBCPP_INLINE_VISIBILITY
5454    result_type max() const {return numeric_limits<result_type>::infinity();}
5455
5456    friend _LIBCPP_INLINE_VISIBILITY
5457        bool operator==(const chi_squared_distribution& __x,
5458                        const chi_squared_distribution& __y)
5459        {return __x.__p_ == __y.__p_;}
5460    friend _LIBCPP_INLINE_VISIBILITY
5461        bool operator!=(const chi_squared_distribution& __x,
5462                        const chi_squared_distribution& __y)
5463        {return !(__x == __y);}
5464};
5465
5466template <class _CharT, class _Traits, class _RT>
5467basic_ostream<_CharT, _Traits>&
5468operator<<(basic_ostream<_CharT, _Traits>& __os,
5469           const chi_squared_distribution<_RT>& __x)
5470{
5471    __save_flags<_CharT, _Traits> __lx(__os);
5472    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5473               ios_base::scientific);
5474    __os << __x.n();
5475    return __os;
5476}
5477
5478template <class _CharT, class _Traits, class _RT>
5479basic_istream<_CharT, _Traits>&
5480operator>>(basic_istream<_CharT, _Traits>& __is,
5481           chi_squared_distribution<_RT>& __x)
5482{
5483    typedef chi_squared_distribution<_RT> _Eng;
5484    typedef typename _Eng::result_type result_type;
5485    typedef typename _Eng::param_type param_type;
5486    __save_flags<_CharT, _Traits> __lx(__is);
5487    __is.flags(ios_base::dec | ios_base::skipws);
5488    result_type __n;
5489    __is >> __n;
5490    if (!__is.fail())
5491        __x.param(param_type(__n));
5492    return __is;
5493}
5494
5495// cauchy_distribution
5496
5497template<class _RealType = double>
5498class _LIBCPP_TEMPLATE_VIS cauchy_distribution
5499{
5500public:
5501    // types
5502    typedef _RealType result_type;
5503
5504    class _LIBCPP_TEMPLATE_VIS param_type
5505    {
5506        result_type __a_;
5507        result_type __b_;
5508    public:
5509        typedef cauchy_distribution distribution_type;
5510
5511        _LIBCPP_INLINE_VISIBILITY
5512        explicit param_type(result_type __a = 0, result_type __b = 1)
5513            : __a_(__a), __b_(__b) {}
5514
5515        _LIBCPP_INLINE_VISIBILITY
5516        result_type a() const {return __a_;}
5517        _LIBCPP_INLINE_VISIBILITY
5518        result_type b() const {return __b_;}
5519
5520        friend _LIBCPP_INLINE_VISIBILITY
5521            bool operator==(const param_type& __x, const param_type& __y)
5522            {return __x.__a_ == __y.__a_ && __x.__b_ == __y.__b_;}
5523        friend _LIBCPP_INLINE_VISIBILITY
5524            bool operator!=(const param_type& __x, const param_type& __y)
5525            {return !(__x == __y);}
5526    };
5527
5528private:
5529    param_type __p_;
5530
5531public:
5532    // constructor and reset functions
5533    _LIBCPP_INLINE_VISIBILITY
5534    explicit cauchy_distribution(result_type __a = 0, result_type __b = 1)
5535        : __p_(param_type(__a, __b)) {}
5536    _LIBCPP_INLINE_VISIBILITY
5537    explicit cauchy_distribution(const param_type& __p)
5538        : __p_(__p) {}
5539    _LIBCPP_INLINE_VISIBILITY
5540    void reset() {}
5541
5542    // generating functions
5543    template<class _URNG>
5544        _LIBCPP_INLINE_VISIBILITY
5545        result_type operator()(_URNG& __g)
5546        {return (*this)(__g, __p_);}
5547    template<class _URNG> _LIBCPP_INLINE_VISIBILITY result_type operator()(_URNG& __g, const param_type& __p);
5548
5549    // property functions
5550    _LIBCPP_INLINE_VISIBILITY
5551    result_type a() const {return __p_.a();}
5552    _LIBCPP_INLINE_VISIBILITY
5553    result_type b() const {return __p_.b();}
5554
5555    _LIBCPP_INLINE_VISIBILITY
5556    param_type param() const {return __p_;}
5557    _LIBCPP_INLINE_VISIBILITY
5558    void param(const param_type& __p) {__p_ = __p;}
5559
5560    _LIBCPP_INLINE_VISIBILITY
5561    result_type min() const {return -numeric_limits<result_type>::infinity();}
5562    _LIBCPP_INLINE_VISIBILITY
5563    result_type max() const {return numeric_limits<result_type>::infinity();}
5564
5565    friend _LIBCPP_INLINE_VISIBILITY
5566        bool operator==(const cauchy_distribution& __x,
5567                        const cauchy_distribution& __y)
5568        {return __x.__p_ == __y.__p_;}
5569    friend _LIBCPP_INLINE_VISIBILITY
5570        bool operator!=(const cauchy_distribution& __x,
5571                        const cauchy_distribution& __y)
5572        {return !(__x == __y);}
5573};
5574
5575template <class _RealType>
5576template<class _URNG>
5577inline
5578_RealType
5579cauchy_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
5580{
5581    uniform_real_distribution<result_type> __gen;
5582    // purposefully let tan arg get as close to pi/2 as it wants, tan will return a finite
5583    return __p.a() + __p.b() * _VSTD::tan(3.1415926535897932384626433832795 * __gen(__g));
5584}
5585
5586template <class _CharT, class _Traits, class _RT>
5587basic_ostream<_CharT, _Traits>&
5588operator<<(basic_ostream<_CharT, _Traits>& __os,
5589           const cauchy_distribution<_RT>& __x)
5590{
5591    __save_flags<_CharT, _Traits> __lx(__os);
5592    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5593               ios_base::scientific);
5594    _CharT __sp = __os.widen(' ');
5595    __os.fill(__sp);
5596    __os << __x.a() << __sp << __x.b();
5597    return __os;
5598}
5599
5600template <class _CharT, class _Traits, class _RT>
5601basic_istream<_CharT, _Traits>&
5602operator>>(basic_istream<_CharT, _Traits>& __is,
5603           cauchy_distribution<_RT>& __x)
5604{
5605    typedef cauchy_distribution<_RT> _Eng;
5606    typedef typename _Eng::result_type result_type;
5607    typedef typename _Eng::param_type param_type;
5608    __save_flags<_CharT, _Traits> __lx(__is);
5609    __is.flags(ios_base::dec | ios_base::skipws);
5610    result_type __a;
5611    result_type __b;
5612    __is >> __a >> __b;
5613    if (!__is.fail())
5614        __x.param(param_type(__a, __b));
5615    return __is;
5616}
5617
5618// fisher_f_distribution
5619
5620template<class _RealType = double>
5621class _LIBCPP_TEMPLATE_VIS fisher_f_distribution
5622{
5623public:
5624    // types
5625    typedef _RealType result_type;
5626
5627    class _LIBCPP_TEMPLATE_VIS param_type
5628    {
5629        result_type __m_;
5630        result_type __n_;
5631    public:
5632        typedef fisher_f_distribution distribution_type;
5633
5634        _LIBCPP_INLINE_VISIBILITY
5635        explicit param_type(result_type __m = 1, result_type __n = 1)
5636            : __m_(__m), __n_(__n) {}
5637
5638        _LIBCPP_INLINE_VISIBILITY
5639        result_type m() const {return __m_;}
5640        _LIBCPP_INLINE_VISIBILITY
5641        result_type n() const {return __n_;}
5642
5643        friend _LIBCPP_INLINE_VISIBILITY
5644            bool operator==(const param_type& __x, const param_type& __y)
5645            {return __x.__m_ == __y.__m_ && __x.__n_ == __y.__n_;}
5646        friend _LIBCPP_INLINE_VISIBILITY
5647            bool operator!=(const param_type& __x, const param_type& __y)
5648            {return !(__x == __y);}
5649    };
5650
5651private:
5652    param_type __p_;
5653
5654public:
5655    // constructor and reset functions
5656    _LIBCPP_INLINE_VISIBILITY
5657    explicit fisher_f_distribution(result_type __m = 1, result_type __n = 1)
5658        : __p_(param_type(__m, __n)) {}
5659    _LIBCPP_INLINE_VISIBILITY
5660    explicit fisher_f_distribution(const param_type& __p)
5661        : __p_(__p) {}
5662    _LIBCPP_INLINE_VISIBILITY
5663    void reset() {}
5664
5665    // generating functions
5666    template<class _URNG>
5667        _LIBCPP_INLINE_VISIBILITY
5668        result_type operator()(_URNG& __g)
5669        {return (*this)(__g, __p_);}
5670    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
5671
5672    // property functions
5673    _LIBCPP_INLINE_VISIBILITY
5674    result_type m() const {return __p_.m();}
5675    _LIBCPP_INLINE_VISIBILITY
5676    result_type n() const {return __p_.n();}
5677
5678    _LIBCPP_INLINE_VISIBILITY
5679    param_type param() const {return __p_;}
5680    _LIBCPP_INLINE_VISIBILITY
5681    void param(const param_type& __p) {__p_ = __p;}
5682
5683    _LIBCPP_INLINE_VISIBILITY
5684    result_type min() const {return 0;}
5685    _LIBCPP_INLINE_VISIBILITY
5686    result_type max() const {return numeric_limits<result_type>::infinity();}
5687
5688    friend _LIBCPP_INLINE_VISIBILITY
5689        bool operator==(const fisher_f_distribution& __x,
5690                        const fisher_f_distribution& __y)
5691        {return __x.__p_ == __y.__p_;}
5692    friend _LIBCPP_INLINE_VISIBILITY
5693        bool operator!=(const fisher_f_distribution& __x,
5694                        const fisher_f_distribution& __y)
5695        {return !(__x == __y);}
5696};
5697
5698template <class _RealType>
5699template<class _URNG>
5700_RealType
5701fisher_f_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
5702{
5703    gamma_distribution<result_type> __gdm(__p.m() * result_type(.5));
5704    gamma_distribution<result_type> __gdn(__p.n() * result_type(.5));
5705    return __p.n() * __gdm(__g) / (__p.m() * __gdn(__g));
5706}
5707
5708template <class _CharT, class _Traits, class _RT>
5709basic_ostream<_CharT, _Traits>&
5710operator<<(basic_ostream<_CharT, _Traits>& __os,
5711           const fisher_f_distribution<_RT>& __x)
5712{
5713    __save_flags<_CharT, _Traits> __lx(__os);
5714    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5715               ios_base::scientific);
5716    _CharT __sp = __os.widen(' ');
5717    __os.fill(__sp);
5718    __os << __x.m() << __sp << __x.n();
5719    return __os;
5720}
5721
5722template <class _CharT, class _Traits, class _RT>
5723basic_istream<_CharT, _Traits>&
5724operator>>(basic_istream<_CharT, _Traits>& __is,
5725           fisher_f_distribution<_RT>& __x)
5726{
5727    typedef fisher_f_distribution<_RT> _Eng;
5728    typedef typename _Eng::result_type result_type;
5729    typedef typename _Eng::param_type param_type;
5730    __save_flags<_CharT, _Traits> __lx(__is);
5731    __is.flags(ios_base::dec | ios_base::skipws);
5732    result_type __m;
5733    result_type __n;
5734    __is >> __m >> __n;
5735    if (!__is.fail())
5736        __x.param(param_type(__m, __n));
5737    return __is;
5738}
5739
5740// student_t_distribution
5741
5742template<class _RealType = double>
5743class _LIBCPP_TEMPLATE_VIS student_t_distribution
5744{
5745public:
5746    // types
5747    typedef _RealType result_type;
5748
5749    class _LIBCPP_TEMPLATE_VIS param_type
5750    {
5751        result_type __n_;
5752    public:
5753        typedef student_t_distribution distribution_type;
5754
5755        _LIBCPP_INLINE_VISIBILITY
5756        explicit param_type(result_type __n = 1) : __n_(__n) {}
5757
5758        _LIBCPP_INLINE_VISIBILITY
5759        result_type n() const {return __n_;}
5760
5761        friend _LIBCPP_INLINE_VISIBILITY
5762            bool operator==(const param_type& __x, const param_type& __y)
5763            {return __x.__n_ == __y.__n_;}
5764        friend _LIBCPP_INLINE_VISIBILITY
5765            bool operator!=(const param_type& __x, const param_type& __y)
5766            {return !(__x == __y);}
5767    };
5768
5769private:
5770    param_type __p_;
5771    normal_distribution<result_type> __nd_;
5772
5773public:
5774    // constructor and reset functions
5775    _LIBCPP_INLINE_VISIBILITY
5776    explicit student_t_distribution(result_type __n = 1)
5777        : __p_(param_type(__n)) {}
5778    _LIBCPP_INLINE_VISIBILITY
5779    explicit student_t_distribution(const param_type& __p)
5780        : __p_(__p) {}
5781    _LIBCPP_INLINE_VISIBILITY
5782    void reset() {__nd_.reset();}
5783
5784    // generating functions
5785    template<class _URNG>
5786        _LIBCPP_INLINE_VISIBILITY
5787        result_type operator()(_URNG& __g)
5788        {return (*this)(__g, __p_);}
5789    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
5790
5791    // property functions
5792    _LIBCPP_INLINE_VISIBILITY
5793    result_type n() const {return __p_.n();}
5794
5795    _LIBCPP_INLINE_VISIBILITY
5796    param_type param() const {return __p_;}
5797    _LIBCPP_INLINE_VISIBILITY
5798    void param(const param_type& __p) {__p_ = __p;}
5799
5800    _LIBCPP_INLINE_VISIBILITY
5801    result_type min() const {return -numeric_limits<result_type>::infinity();}
5802    _LIBCPP_INLINE_VISIBILITY
5803    result_type max() const {return numeric_limits<result_type>::infinity();}
5804
5805    friend _LIBCPP_INLINE_VISIBILITY
5806        bool operator==(const student_t_distribution& __x,
5807                        const student_t_distribution& __y)
5808        {return __x.__p_ == __y.__p_;}
5809    friend _LIBCPP_INLINE_VISIBILITY
5810        bool operator!=(const student_t_distribution& __x,
5811                        const student_t_distribution& __y)
5812        {return !(__x == __y);}
5813};
5814
5815template <class _RealType>
5816template<class _URNG>
5817_RealType
5818student_t_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
5819{
5820    gamma_distribution<result_type> __gd(__p.n() * .5, 2);
5821    return __nd_(__g) * _VSTD::sqrt(__p.n()/__gd(__g));
5822}
5823
5824template <class _CharT, class _Traits, class _RT>
5825basic_ostream<_CharT, _Traits>&
5826operator<<(basic_ostream<_CharT, _Traits>& __os,
5827           const student_t_distribution<_RT>& __x)
5828{
5829    __save_flags<_CharT, _Traits> __lx(__os);
5830    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
5831               ios_base::scientific);
5832    __os << __x.n();
5833    return __os;
5834}
5835
5836template <class _CharT, class _Traits, class _RT>
5837basic_istream<_CharT, _Traits>&
5838operator>>(basic_istream<_CharT, _Traits>& __is,
5839           student_t_distribution<_RT>& __x)
5840{
5841    typedef student_t_distribution<_RT> _Eng;
5842    typedef typename _Eng::result_type result_type;
5843    typedef typename _Eng::param_type param_type;
5844    __save_flags<_CharT, _Traits> __lx(__is);
5845    __is.flags(ios_base::dec | ios_base::skipws);
5846    result_type __n;
5847    __is >> __n;
5848    if (!__is.fail())
5849        __x.param(param_type(__n));
5850    return __is;
5851}
5852
5853// discrete_distribution
5854
5855template<class _IntType = int>
5856class _LIBCPP_TEMPLATE_VIS discrete_distribution
5857{
5858public:
5859    // types
5860    typedef _IntType result_type;
5861
5862    class _LIBCPP_TEMPLATE_VIS param_type
5863    {
5864        vector<double> __p_;
5865    public:
5866        typedef discrete_distribution distribution_type;
5867
5868        _LIBCPP_INLINE_VISIBILITY
5869        param_type() {}
5870        template<class _InputIterator>
5871            _LIBCPP_INLINE_VISIBILITY
5872            param_type(_InputIterator __f, _InputIterator __l)
5873            : __p_(__f, __l) {__init();}
5874#ifndef _LIBCPP_CXX03_LANG
5875        _LIBCPP_INLINE_VISIBILITY
5876        param_type(initializer_list<double> __wl)
5877            : __p_(__wl.begin(), __wl.end()) {__init();}
5878#endif  // _LIBCPP_CXX03_LANG
5879        template<class _UnaryOperation>
5880            param_type(size_t __nw, double __xmin, double __xmax,
5881                       _UnaryOperation __fw);
5882
5883        vector<double> probabilities() const;
5884
5885        friend _LIBCPP_INLINE_VISIBILITY
5886            bool operator==(const param_type& __x, const param_type& __y)
5887            {return __x.__p_ == __y.__p_;}
5888        friend _LIBCPP_INLINE_VISIBILITY
5889            bool operator!=(const param_type& __x, const param_type& __y)
5890            {return !(__x == __y);}
5891
5892    private:
5893        void __init();
5894
5895        friend class discrete_distribution;
5896
5897        template <class _CharT, class _Traits, class _IT>
5898        friend
5899        basic_ostream<_CharT, _Traits>&
5900        operator<<(basic_ostream<_CharT, _Traits>& __os,
5901                   const discrete_distribution<_IT>& __x);
5902
5903        template <class _CharT, class _Traits, class _IT>
5904        friend
5905        basic_istream<_CharT, _Traits>&
5906        operator>>(basic_istream<_CharT, _Traits>& __is,
5907                   discrete_distribution<_IT>& __x);
5908    };
5909
5910private:
5911    param_type __p_;
5912
5913public:
5914    // constructor and reset functions
5915    _LIBCPP_INLINE_VISIBILITY
5916    discrete_distribution() {}
5917    template<class _InputIterator>
5918        _LIBCPP_INLINE_VISIBILITY
5919        discrete_distribution(_InputIterator __f, _InputIterator __l)
5920            : __p_(__f, __l) {}
5921#ifndef _LIBCPP_CXX03_LANG
5922    _LIBCPP_INLINE_VISIBILITY
5923    discrete_distribution(initializer_list<double> __wl)
5924        : __p_(__wl) {}
5925#endif  // _LIBCPP_CXX03_LANG
5926    template<class _UnaryOperation>
5927        _LIBCPP_INLINE_VISIBILITY
5928        discrete_distribution(size_t __nw, double __xmin, double __xmax,
5929                              _UnaryOperation __fw)
5930        : __p_(__nw, __xmin, __xmax, __fw) {}
5931    _LIBCPP_INLINE_VISIBILITY
5932    explicit discrete_distribution(const param_type& __p)
5933        : __p_(__p) {}
5934    _LIBCPP_INLINE_VISIBILITY
5935    void reset() {}
5936
5937    // generating functions
5938    template<class _URNG>
5939        _LIBCPP_INLINE_VISIBILITY
5940        result_type operator()(_URNG& __g)
5941        {return (*this)(__g, __p_);}
5942    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
5943
5944    // property functions
5945    _LIBCPP_INLINE_VISIBILITY
5946    vector<double> probabilities() const {return __p_.probabilities();}
5947
5948    _LIBCPP_INLINE_VISIBILITY
5949    param_type param() const {return __p_;}
5950    _LIBCPP_INLINE_VISIBILITY
5951    void param(const param_type& __p) {__p_ = __p;}
5952
5953    _LIBCPP_INLINE_VISIBILITY
5954    result_type min() const {return 0;}
5955    _LIBCPP_INLINE_VISIBILITY
5956    result_type max() const {return __p_.__p_.size();}
5957
5958    friend _LIBCPP_INLINE_VISIBILITY
5959        bool operator==(const discrete_distribution& __x,
5960                        const discrete_distribution& __y)
5961        {return __x.__p_ == __y.__p_;}
5962    friend _LIBCPP_INLINE_VISIBILITY
5963        bool operator!=(const discrete_distribution& __x,
5964                        const discrete_distribution& __y)
5965        {return !(__x == __y);}
5966
5967    template <class _CharT, class _Traits, class _IT>
5968    friend
5969    basic_ostream<_CharT, _Traits>&
5970    operator<<(basic_ostream<_CharT, _Traits>& __os,
5971               const discrete_distribution<_IT>& __x);
5972
5973    template <class _CharT, class _Traits, class _IT>
5974    friend
5975    basic_istream<_CharT, _Traits>&
5976    operator>>(basic_istream<_CharT, _Traits>& __is,
5977               discrete_distribution<_IT>& __x);
5978};
5979
5980template<class _IntType>
5981template<class _UnaryOperation>
5982discrete_distribution<_IntType>::param_type::param_type(size_t __nw,
5983                                                        double __xmin,
5984                                                        double __xmax,
5985                                                        _UnaryOperation __fw)
5986{
5987    if (__nw > 1)
5988    {
5989        __p_.reserve(__nw - 1);
5990        double __d = (__xmax - __xmin) / __nw;
5991        double __d2 = __d / 2;
5992        for (size_t __k = 0; __k < __nw; ++__k)
5993            __p_.push_back(__fw(__xmin + __k * __d + __d2));
5994        __init();
5995    }
5996}
5997
5998template<class _IntType>
5999void
6000discrete_distribution<_IntType>::param_type::__init()
6001{
6002    if (!__p_.empty())
6003    {
6004        if (__p_.size() > 1)
6005        {
6006            double __s = _VSTD::accumulate(__p_.begin(), __p_.end(), 0.0);
6007            for (_VSTD::vector<double>::iterator __i = __p_.begin(), __e = __p_.end();
6008                                                                       __i < __e; ++__i)
6009                *__i /= __s;
6010            vector<double> __t(__p_.size() - 1);
6011            _VSTD::partial_sum(__p_.begin(), __p_.end() - 1, __t.begin());
6012            swap(__p_, __t);
6013        }
6014        else
6015        {
6016            __p_.clear();
6017            __p_.shrink_to_fit();
6018        }
6019    }
6020}
6021
6022template<class _IntType>
6023vector<double>
6024discrete_distribution<_IntType>::param_type::probabilities() const
6025{
6026    size_t __n = __p_.size();
6027    _VSTD::vector<double> __p(__n+1);
6028    _VSTD::adjacent_difference(__p_.begin(), __p_.end(), __p.begin());
6029    if (__n > 0)
6030        __p[__n] = 1 - __p_[__n-1];
6031    else
6032        __p[0] = 1;
6033    return __p;
6034}
6035
6036template<class _IntType>
6037template<class _URNG>
6038_IntType
6039discrete_distribution<_IntType>::operator()(_URNG& __g, const param_type& __p)
6040{
6041    uniform_real_distribution<double> __gen;
6042    return static_cast<_IntType>(
6043           _VSTD::upper_bound(__p.__p_.begin(), __p.__p_.end(), __gen(__g)) -
6044                                                              __p.__p_.begin());
6045}
6046
6047template <class _CharT, class _Traits, class _IT>
6048basic_ostream<_CharT, _Traits>&
6049operator<<(basic_ostream<_CharT, _Traits>& __os,
6050           const discrete_distribution<_IT>& __x)
6051{
6052    __save_flags<_CharT, _Traits> __lx(__os);
6053    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
6054               ios_base::scientific);
6055    _CharT __sp = __os.widen(' ');
6056    __os.fill(__sp);
6057    size_t __n = __x.__p_.__p_.size();
6058    __os << __n;
6059    for (size_t __i = 0; __i < __n; ++__i)
6060        __os << __sp << __x.__p_.__p_[__i];
6061    return __os;
6062}
6063
6064template <class _CharT, class _Traits, class _IT>
6065basic_istream<_CharT, _Traits>&
6066operator>>(basic_istream<_CharT, _Traits>& __is,
6067           discrete_distribution<_IT>& __x)
6068{
6069    __save_flags<_CharT, _Traits> __lx(__is);
6070    __is.flags(ios_base::dec | ios_base::skipws);
6071    size_t __n;
6072    __is >> __n;
6073    vector<double> __p(__n);
6074    for (size_t __i = 0; __i < __n; ++__i)
6075        __is >> __p[__i];
6076    if (!__is.fail())
6077        swap(__x.__p_.__p_, __p);
6078    return __is;
6079}
6080
6081// piecewise_constant_distribution
6082
6083template<class _RealType = double>
6084class _LIBCPP_TEMPLATE_VIS piecewise_constant_distribution
6085{
6086public:
6087    // types
6088    typedef _RealType result_type;
6089
6090    class _LIBCPP_TEMPLATE_VIS param_type
6091    {
6092        vector<result_type> __b_;
6093        vector<result_type> __densities_;
6094        vector<result_type> __areas_;
6095    public:
6096        typedef piecewise_constant_distribution distribution_type;
6097
6098        param_type();
6099        template<class _InputIteratorB, class _InputIteratorW>
6100            param_type(_InputIteratorB __fB, _InputIteratorB __lB,
6101                       _InputIteratorW __fW);
6102#ifndef _LIBCPP_CXX03_LANG
6103        template<class _UnaryOperation>
6104            param_type(initializer_list<result_type> __bl, _UnaryOperation __fw);
6105#endif  // _LIBCPP_CXX03_LANG
6106        template<class _UnaryOperation>
6107            param_type(size_t __nw, result_type __xmin, result_type __xmax,
6108                       _UnaryOperation __fw);
6109        param_type & operator=(const param_type& __rhs);
6110
6111        _LIBCPP_INLINE_VISIBILITY
6112        vector<result_type> intervals() const {return __b_;}
6113        _LIBCPP_INLINE_VISIBILITY
6114        vector<result_type> densities() const {return __densities_;}
6115
6116        friend _LIBCPP_INLINE_VISIBILITY
6117            bool operator==(const param_type& __x, const param_type& __y)
6118            {return __x.__densities_ == __y.__densities_ && __x.__b_ == __y.__b_;}
6119        friend _LIBCPP_INLINE_VISIBILITY
6120            bool operator!=(const param_type& __x, const param_type& __y)
6121            {return !(__x == __y);}
6122
6123    private:
6124        void __init();
6125
6126        friend class piecewise_constant_distribution;
6127
6128        template <class _CharT, class _Traits, class _RT>
6129        friend
6130        basic_ostream<_CharT, _Traits>&
6131        operator<<(basic_ostream<_CharT, _Traits>& __os,
6132                   const piecewise_constant_distribution<_RT>& __x);
6133
6134        template <class _CharT, class _Traits, class _RT>
6135        friend
6136        basic_istream<_CharT, _Traits>&
6137        operator>>(basic_istream<_CharT, _Traits>& __is,
6138                   piecewise_constant_distribution<_RT>& __x);
6139    };
6140
6141private:
6142    param_type __p_;
6143
6144public:
6145    // constructor and reset functions
6146    _LIBCPP_INLINE_VISIBILITY
6147    piecewise_constant_distribution() {}
6148    template<class _InputIteratorB, class _InputIteratorW>
6149        _LIBCPP_INLINE_VISIBILITY
6150        piecewise_constant_distribution(_InputIteratorB __fB,
6151                                        _InputIteratorB __lB,
6152                                        _InputIteratorW __fW)
6153        : __p_(__fB, __lB, __fW) {}
6154
6155#ifndef _LIBCPP_CXX03_LANG
6156    template<class _UnaryOperation>
6157        _LIBCPP_INLINE_VISIBILITY
6158        piecewise_constant_distribution(initializer_list<result_type> __bl,
6159                                        _UnaryOperation __fw)
6160        : __p_(__bl, __fw) {}
6161#endif  // _LIBCPP_CXX03_LANG
6162
6163    template<class _UnaryOperation>
6164        _LIBCPP_INLINE_VISIBILITY
6165        piecewise_constant_distribution(size_t __nw, result_type __xmin,
6166                                        result_type __xmax, _UnaryOperation __fw)
6167        : __p_(__nw, __xmin, __xmax, __fw) {}
6168
6169    _LIBCPP_INLINE_VISIBILITY
6170    explicit piecewise_constant_distribution(const param_type& __p)
6171        : __p_(__p) {}
6172
6173    _LIBCPP_INLINE_VISIBILITY
6174    void reset() {}
6175
6176    // generating functions
6177    template<class _URNG>
6178        _LIBCPP_INLINE_VISIBILITY
6179        result_type operator()(_URNG& __g)
6180        {return (*this)(__g, __p_);}
6181    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
6182
6183    // property functions
6184    _LIBCPP_INLINE_VISIBILITY
6185    vector<result_type> intervals() const {return __p_.intervals();}
6186    _LIBCPP_INLINE_VISIBILITY
6187    vector<result_type> densities() const {return __p_.densities();}
6188
6189    _LIBCPP_INLINE_VISIBILITY
6190    param_type param() const {return __p_;}
6191    _LIBCPP_INLINE_VISIBILITY
6192    void param(const param_type& __p) {__p_ = __p;}
6193
6194    _LIBCPP_INLINE_VISIBILITY
6195    result_type min() const {return __p_.__b_.front();}
6196    _LIBCPP_INLINE_VISIBILITY
6197    result_type max() const {return __p_.__b_.back();}
6198
6199    friend _LIBCPP_INLINE_VISIBILITY
6200        bool operator==(const piecewise_constant_distribution& __x,
6201                        const piecewise_constant_distribution& __y)
6202        {return __x.__p_ == __y.__p_;}
6203    friend _LIBCPP_INLINE_VISIBILITY
6204        bool operator!=(const piecewise_constant_distribution& __x,
6205                           const piecewise_constant_distribution& __y)
6206        {return !(__x == __y);}
6207
6208    template <class _CharT, class _Traits, class _RT>
6209    friend
6210    basic_ostream<_CharT, _Traits>&
6211    operator<<(basic_ostream<_CharT, _Traits>& __os,
6212               const piecewise_constant_distribution<_RT>& __x);
6213
6214    template <class _CharT, class _Traits, class _RT>
6215    friend
6216    basic_istream<_CharT, _Traits>&
6217    operator>>(basic_istream<_CharT, _Traits>& __is,
6218               piecewise_constant_distribution<_RT>& __x);
6219};
6220
6221template<class _RealType>
6222typename piecewise_constant_distribution<_RealType>::param_type &
6223piecewise_constant_distribution<_RealType>::param_type::operator=
6224                                                       (const param_type& __rhs)
6225{
6226//  These can throw
6227    __b_.reserve        (__rhs.__b_.size ());
6228    __densities_.reserve(__rhs.__densities_.size());
6229    __areas_.reserve    (__rhs.__areas_.size());
6230
6231//  These can not throw
6232    __b_         = __rhs.__b_;
6233    __densities_ = __rhs.__densities_;
6234    __areas_     =  __rhs.__areas_;
6235    return *this;
6236}
6237
6238template<class _RealType>
6239void
6240piecewise_constant_distribution<_RealType>::param_type::__init()
6241{
6242    // __densities_ contains non-normalized areas
6243    result_type __total_area = _VSTD::accumulate(__densities_.begin(),
6244                                                __densities_.end(),
6245                                                result_type());
6246    for (size_t __i = 0; __i < __densities_.size(); ++__i)
6247        __densities_[__i] /= __total_area;
6248    // __densities_ contains normalized areas
6249    __areas_.assign(__densities_.size(), result_type());
6250    _VSTD::partial_sum(__densities_.begin(), __densities_.end() - 1,
6251                                                          __areas_.begin() + 1);
6252    // __areas_ contains partial sums of normalized areas: [0, __densities_ - 1]
6253    __densities_.back() = 1 - __areas_.back();  // correct round off error
6254    for (size_t __i = 0; __i < __densities_.size(); ++__i)
6255        __densities_[__i] /= (__b_[__i+1] - __b_[__i]);
6256    // __densities_ now contains __densities_
6257}
6258
6259template<class _RealType>
6260piecewise_constant_distribution<_RealType>::param_type::param_type()
6261    : __b_(2),
6262      __densities_(1, 1.0),
6263      __areas_(1, 0.0)
6264{
6265    __b_[1] = 1;
6266}
6267
6268template<class _RealType>
6269template<class _InputIteratorB, class _InputIteratorW>
6270piecewise_constant_distribution<_RealType>::param_type::param_type(
6271        _InputIteratorB __fB, _InputIteratorB __lB, _InputIteratorW __fW)
6272    : __b_(__fB, __lB)
6273{
6274    if (__b_.size() < 2)
6275    {
6276        __b_.resize(2);
6277        __b_[0] = 0;
6278        __b_[1] = 1;
6279        __densities_.assign(1, 1.0);
6280        __areas_.assign(1, 0.0);
6281    }
6282    else
6283    {
6284        __densities_.reserve(__b_.size() - 1);
6285        for (size_t __i = 0; __i < __b_.size() - 1; ++__i, ++__fW)
6286            __densities_.push_back(*__fW);
6287        __init();
6288    }
6289}
6290
6291#ifndef _LIBCPP_CXX03_LANG
6292
6293template<class _RealType>
6294template<class _UnaryOperation>
6295piecewise_constant_distribution<_RealType>::param_type::param_type(
6296        initializer_list<result_type> __bl, _UnaryOperation __fw)
6297    : __b_(__bl.begin(), __bl.end())
6298{
6299    if (__b_.size() < 2)
6300    {
6301        __b_.resize(2);
6302        __b_[0] = 0;
6303        __b_[1] = 1;
6304        __densities_.assign(1, 1.0);
6305        __areas_.assign(1, 0.0);
6306    }
6307    else
6308    {
6309        __densities_.reserve(__b_.size() - 1);
6310        for (size_t __i = 0; __i < __b_.size() - 1; ++__i)
6311            __densities_.push_back(__fw((__b_[__i+1] + __b_[__i])*.5));
6312        __init();
6313    }
6314}
6315
6316#endif  // _LIBCPP_CXX03_LANG
6317
6318template<class _RealType>
6319template<class _UnaryOperation>
6320piecewise_constant_distribution<_RealType>::param_type::param_type(
6321        size_t __nw, result_type __xmin, result_type __xmax, _UnaryOperation __fw)
6322    : __b_(__nw == 0 ? 2 : __nw + 1)
6323{
6324    size_t __n = __b_.size() - 1;
6325    result_type __d = (__xmax - __xmin) / __n;
6326    __densities_.reserve(__n);
6327    for (size_t __i = 0; __i < __n; ++__i)
6328    {
6329        __b_[__i] = __xmin + __i * __d;
6330        __densities_.push_back(__fw(__b_[__i] + __d*.5));
6331    }
6332    __b_[__n] = __xmax;
6333    __init();
6334}
6335
6336template<class _RealType>
6337template<class _URNG>
6338_RealType
6339piecewise_constant_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
6340{
6341    typedef uniform_real_distribution<result_type> _Gen;
6342    result_type __u = _Gen()(__g);
6343    ptrdiff_t __k = _VSTD::upper_bound(__p.__areas_.begin(), __p.__areas_.end(),
6344                                      __u) - __p.__areas_.begin() - 1;
6345    return (__u - __p.__areas_[__k]) / __p.__densities_[__k] + __p.__b_[__k];
6346}
6347
6348template <class _CharT, class _Traits, class _RT>
6349basic_ostream<_CharT, _Traits>&
6350operator<<(basic_ostream<_CharT, _Traits>& __os,
6351           const piecewise_constant_distribution<_RT>& __x)
6352{
6353    __save_flags<_CharT, _Traits> __lx(__os);
6354    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
6355               ios_base::scientific);
6356    _CharT __sp = __os.widen(' ');
6357    __os.fill(__sp);
6358    size_t __n = __x.__p_.__b_.size();
6359    __os << __n;
6360    for (size_t __i = 0; __i < __n; ++__i)
6361        __os << __sp << __x.__p_.__b_[__i];
6362    __n = __x.__p_.__densities_.size();
6363    __os << __sp << __n;
6364    for (size_t __i = 0; __i < __n; ++__i)
6365        __os << __sp << __x.__p_.__densities_[__i];
6366    __n = __x.__p_.__areas_.size();
6367    __os << __sp << __n;
6368    for (size_t __i = 0; __i < __n; ++__i)
6369        __os << __sp << __x.__p_.__areas_[__i];
6370    return __os;
6371}
6372
6373template <class _CharT, class _Traits, class _RT>
6374basic_istream<_CharT, _Traits>&
6375operator>>(basic_istream<_CharT, _Traits>& __is,
6376           piecewise_constant_distribution<_RT>& __x)
6377{
6378    typedef piecewise_constant_distribution<_RT> _Eng;
6379    typedef typename _Eng::result_type result_type;
6380    __save_flags<_CharT, _Traits> __lx(__is);
6381    __is.flags(ios_base::dec | ios_base::skipws);
6382    size_t __n;
6383    __is >> __n;
6384    vector<result_type> __b(__n);
6385    for (size_t __i = 0; __i < __n; ++__i)
6386        __is >> __b[__i];
6387    __is >> __n;
6388    vector<result_type> __densities(__n);
6389    for (size_t __i = 0; __i < __n; ++__i)
6390        __is >> __densities[__i];
6391    __is >> __n;
6392    vector<result_type> __areas(__n);
6393    for (size_t __i = 0; __i < __n; ++__i)
6394        __is >> __areas[__i];
6395    if (!__is.fail())
6396    {
6397        swap(__x.__p_.__b_, __b);
6398        swap(__x.__p_.__densities_, __densities);
6399        swap(__x.__p_.__areas_, __areas);
6400    }
6401    return __is;
6402}
6403
6404// piecewise_linear_distribution
6405
6406template<class _RealType = double>
6407class _LIBCPP_TEMPLATE_VIS piecewise_linear_distribution
6408{
6409public:
6410    // types
6411    typedef _RealType result_type;
6412
6413    class _LIBCPP_TEMPLATE_VIS param_type
6414    {
6415        vector<result_type> __b_;
6416        vector<result_type> __densities_;
6417        vector<result_type> __areas_;
6418    public:
6419        typedef piecewise_linear_distribution distribution_type;
6420
6421        param_type();
6422        template<class _InputIteratorB, class _InputIteratorW>
6423            param_type(_InputIteratorB __fB, _InputIteratorB __lB,
6424                       _InputIteratorW __fW);
6425#ifndef _LIBCPP_CXX03_LANG
6426        template<class _UnaryOperation>
6427            param_type(initializer_list<result_type> __bl, _UnaryOperation __fw);
6428#endif  // _LIBCPP_CXX03_LANG
6429        template<class _UnaryOperation>
6430            param_type(size_t __nw, result_type __xmin, result_type __xmax,
6431                       _UnaryOperation __fw);
6432        param_type & operator=(const param_type& __rhs);
6433
6434        _LIBCPP_INLINE_VISIBILITY
6435        vector<result_type> intervals() const {return __b_;}
6436        _LIBCPP_INLINE_VISIBILITY
6437        vector<result_type> densities() const {return __densities_;}
6438
6439        friend _LIBCPP_INLINE_VISIBILITY
6440            bool operator==(const param_type& __x, const param_type& __y)
6441            {return __x.__densities_ == __y.__densities_ && __x.__b_ == __y.__b_;}
6442        friend _LIBCPP_INLINE_VISIBILITY
6443            bool operator!=(const param_type& __x, const param_type& __y)
6444            {return !(__x == __y);}
6445
6446    private:
6447        void __init();
6448
6449        friend class piecewise_linear_distribution;
6450
6451        template <class _CharT, class _Traits, class _RT>
6452        friend
6453        basic_ostream<_CharT, _Traits>&
6454        operator<<(basic_ostream<_CharT, _Traits>& __os,
6455                   const piecewise_linear_distribution<_RT>& __x);
6456
6457        template <class _CharT, class _Traits, class _RT>
6458        friend
6459        basic_istream<_CharT, _Traits>&
6460        operator>>(basic_istream<_CharT, _Traits>& __is,
6461                   piecewise_linear_distribution<_RT>& __x);
6462    };
6463
6464private:
6465    param_type __p_;
6466
6467public:
6468    // constructor and reset functions
6469    _LIBCPP_INLINE_VISIBILITY
6470    piecewise_linear_distribution() {}
6471    template<class _InputIteratorB, class _InputIteratorW>
6472        _LIBCPP_INLINE_VISIBILITY
6473        piecewise_linear_distribution(_InputIteratorB __fB,
6474                                      _InputIteratorB __lB,
6475                                      _InputIteratorW __fW)
6476        : __p_(__fB, __lB, __fW) {}
6477
6478#ifndef _LIBCPP_CXX03_LANG
6479    template<class _UnaryOperation>
6480        _LIBCPP_INLINE_VISIBILITY
6481        piecewise_linear_distribution(initializer_list<result_type> __bl,
6482                                      _UnaryOperation __fw)
6483        : __p_(__bl, __fw) {}
6484#endif  // _LIBCPP_CXX03_LANG
6485
6486    template<class _UnaryOperation>
6487        _LIBCPP_INLINE_VISIBILITY
6488        piecewise_linear_distribution(size_t __nw, result_type __xmin,
6489                                      result_type __xmax, _UnaryOperation __fw)
6490        : __p_(__nw, __xmin, __xmax, __fw) {}
6491
6492    _LIBCPP_INLINE_VISIBILITY
6493    explicit piecewise_linear_distribution(const param_type& __p)
6494        : __p_(__p) {}
6495
6496    _LIBCPP_INLINE_VISIBILITY
6497    void reset() {}
6498
6499    // generating functions
6500    template<class _URNG>
6501        _LIBCPP_INLINE_VISIBILITY
6502        result_type operator()(_URNG& __g)
6503        {return (*this)(__g, __p_);}
6504    template<class _URNG> result_type operator()(_URNG& __g, const param_type& __p);
6505
6506    // property functions
6507    _LIBCPP_INLINE_VISIBILITY
6508    vector<result_type> intervals() const {return __p_.intervals();}
6509    _LIBCPP_INLINE_VISIBILITY
6510    vector<result_type> densities() const {return __p_.densities();}
6511
6512    _LIBCPP_INLINE_VISIBILITY
6513    param_type param() const {return __p_;}
6514    _LIBCPP_INLINE_VISIBILITY
6515    void param(const param_type& __p) {__p_ = __p;}
6516
6517    _LIBCPP_INLINE_VISIBILITY
6518    result_type min() const {return __p_.__b_.front();}
6519    _LIBCPP_INLINE_VISIBILITY
6520    result_type max() const {return __p_.__b_.back();}
6521
6522    friend _LIBCPP_INLINE_VISIBILITY
6523        bool operator==(const piecewise_linear_distribution& __x,
6524                        const piecewise_linear_distribution& __y)
6525        {return __x.__p_ == __y.__p_;}
6526    friend _LIBCPP_INLINE_VISIBILITY
6527        bool operator!=(const piecewise_linear_distribution& __x,
6528                        const piecewise_linear_distribution& __y)
6529        {return !(__x == __y);}
6530
6531    template <class _CharT, class _Traits, class _RT>
6532    friend
6533    basic_ostream<_CharT, _Traits>&
6534    operator<<(basic_ostream<_CharT, _Traits>& __os,
6535               const piecewise_linear_distribution<_RT>& __x);
6536
6537    template <class _CharT, class _Traits, class _RT>
6538    friend
6539    basic_istream<_CharT, _Traits>&
6540    operator>>(basic_istream<_CharT, _Traits>& __is,
6541               piecewise_linear_distribution<_RT>& __x);
6542};
6543
6544template<class _RealType>
6545typename piecewise_linear_distribution<_RealType>::param_type &
6546piecewise_linear_distribution<_RealType>::param_type::operator=
6547                                                       (const param_type& __rhs)
6548{
6549//  These can throw
6550    __b_.reserve        (__rhs.__b_.size ());
6551    __densities_.reserve(__rhs.__densities_.size());
6552    __areas_.reserve    (__rhs.__areas_.size());
6553
6554//  These can not throw
6555    __b_         = __rhs.__b_;
6556    __densities_ = __rhs.__densities_;
6557    __areas_     =  __rhs.__areas_;
6558    return *this;
6559}
6560
6561
6562template<class _RealType>
6563void
6564piecewise_linear_distribution<_RealType>::param_type::__init()
6565{
6566    __areas_.assign(__densities_.size() - 1, result_type());
6567    result_type _Sp = 0;
6568    for (size_t __i = 0; __i < __areas_.size(); ++__i)
6569    {
6570        __areas_[__i] = (__densities_[__i+1] + __densities_[__i]) *
6571                        (__b_[__i+1] - __b_[__i]) * .5;
6572        _Sp += __areas_[__i];
6573    }
6574    for (size_t __i = __areas_.size(); __i > 1;)
6575    {
6576        --__i;
6577        __areas_[__i] = __areas_[__i-1] / _Sp;
6578    }
6579    __areas_[0] = 0;
6580    for (size_t __i = 1; __i < __areas_.size(); ++__i)
6581        __areas_[__i] += __areas_[__i-1];
6582    for (size_t __i = 0; __i < __densities_.size(); ++__i)
6583        __densities_[__i] /= _Sp;
6584}
6585
6586template<class _RealType>
6587piecewise_linear_distribution<_RealType>::param_type::param_type()
6588    : __b_(2),
6589      __densities_(2, 1.0),
6590      __areas_(1, 0.0)
6591{
6592    __b_[1] = 1;
6593}
6594
6595template<class _RealType>
6596template<class _InputIteratorB, class _InputIteratorW>
6597piecewise_linear_distribution<_RealType>::param_type::param_type(
6598        _InputIteratorB __fB, _InputIteratorB __lB, _InputIteratorW __fW)
6599    : __b_(__fB, __lB)
6600{
6601    if (__b_.size() < 2)
6602    {
6603        __b_.resize(2);
6604        __b_[0] = 0;
6605        __b_[1] = 1;
6606        __densities_.assign(2, 1.0);
6607        __areas_.assign(1, 0.0);
6608    }
6609    else
6610    {
6611        __densities_.reserve(__b_.size());
6612        for (size_t __i = 0; __i < __b_.size(); ++__i, ++__fW)
6613            __densities_.push_back(*__fW);
6614        __init();
6615    }
6616}
6617
6618#ifndef _LIBCPP_CXX03_LANG
6619
6620template<class _RealType>
6621template<class _UnaryOperation>
6622piecewise_linear_distribution<_RealType>::param_type::param_type(
6623        initializer_list<result_type> __bl, _UnaryOperation __fw)
6624    : __b_(__bl.begin(), __bl.end())
6625{
6626    if (__b_.size() < 2)
6627    {
6628        __b_.resize(2);
6629        __b_[0] = 0;
6630        __b_[1] = 1;
6631        __densities_.assign(2, 1.0);
6632        __areas_.assign(1, 0.0);
6633    }
6634    else
6635    {
6636        __densities_.reserve(__b_.size());
6637        for (size_t __i = 0; __i < __b_.size(); ++__i)
6638            __densities_.push_back(__fw(__b_[__i]));
6639        __init();
6640    }
6641}
6642
6643#endif  // _LIBCPP_CXX03_LANG
6644
6645template<class _RealType>
6646template<class _UnaryOperation>
6647piecewise_linear_distribution<_RealType>::param_type::param_type(
6648        size_t __nw, result_type __xmin, result_type __xmax, _UnaryOperation __fw)
6649    : __b_(__nw == 0 ? 2 : __nw + 1)
6650{
6651    size_t __n = __b_.size() - 1;
6652    result_type __d = (__xmax - __xmin) / __n;
6653    __densities_.reserve(__b_.size());
6654    for (size_t __i = 0; __i < __n; ++__i)
6655    {
6656        __b_[__i] = __xmin + __i * __d;
6657        __densities_.push_back(__fw(__b_[__i]));
6658    }
6659    __b_[__n] = __xmax;
6660    __densities_.push_back(__fw(__b_[__n]));
6661    __init();
6662}
6663
6664template<class _RealType>
6665template<class _URNG>
6666_RealType
6667piecewise_linear_distribution<_RealType>::operator()(_URNG& __g, const param_type& __p)
6668{
6669    typedef uniform_real_distribution<result_type> _Gen;
6670    result_type __u = _Gen()(__g);
6671    ptrdiff_t __k = _VSTD::upper_bound(__p.__areas_.begin(), __p.__areas_.end(),
6672                                      __u) - __p.__areas_.begin() - 1;
6673    __u -= __p.__areas_[__k];
6674    const result_type __dk = __p.__densities_[__k];
6675    const result_type __dk1 = __p.__densities_[__k+1];
6676    const result_type __deltad = __dk1 - __dk;
6677    const result_type __bk = __p.__b_[__k];
6678    if (__deltad == 0)
6679        return __u / __dk + __bk;
6680    const result_type __bk1 = __p.__b_[__k+1];
6681    const result_type __deltab = __bk1 - __bk;
6682    return (__bk * __dk1 - __bk1 * __dk +
6683        _VSTD::sqrt(__deltab * (__deltab * __dk * __dk + 2 * __deltad * __u))) /
6684        __deltad;
6685}
6686
6687template <class _CharT, class _Traits, class _RT>
6688basic_ostream<_CharT, _Traits>&
6689operator<<(basic_ostream<_CharT, _Traits>& __os,
6690           const piecewise_linear_distribution<_RT>& __x)
6691{
6692    __save_flags<_CharT, _Traits> __lx(__os);
6693    __os.flags(ios_base::dec | ios_base::left | ios_base::fixed |
6694               ios_base::scientific);
6695    _CharT __sp = __os.widen(' ');
6696    __os.fill(__sp);
6697    size_t __n = __x.__p_.__b_.size();
6698    __os << __n;
6699    for (size_t __i = 0; __i < __n; ++__i)
6700        __os << __sp << __x.__p_.__b_[__i];
6701    __n = __x.__p_.__densities_.size();
6702    __os << __sp << __n;
6703    for (size_t __i = 0; __i < __n; ++__i)
6704        __os << __sp << __x.__p_.__densities_[__i];
6705    __n = __x.__p_.__areas_.size();
6706    __os << __sp << __n;
6707    for (size_t __i = 0; __i < __n; ++__i)
6708        __os << __sp << __x.__p_.__areas_[__i];
6709    return __os;
6710}
6711
6712template <class _CharT, class _Traits, class _RT>
6713basic_istream<_CharT, _Traits>&
6714operator>>(basic_istream<_CharT, _Traits>& __is,
6715           piecewise_linear_distribution<_RT>& __x)
6716{
6717    typedef piecewise_linear_distribution<_RT> _Eng;
6718    typedef typename _Eng::result_type result_type;
6719    __save_flags<_CharT, _Traits> __lx(__is);
6720    __is.flags(ios_base::dec | ios_base::skipws);
6721    size_t __n;
6722    __is >> __n;
6723    vector<result_type> __b(__n);
6724    for (size_t __i = 0; __i < __n; ++__i)
6725        __is >> __b[__i];
6726    __is >> __n;
6727    vector<result_type> __densities(__n);
6728    for (size_t __i = 0; __i < __n; ++__i)
6729        __is >> __densities[__i];
6730    __is >> __n;
6731    vector<result_type> __areas(__n);
6732    for (size_t __i = 0; __i < __n; ++__i)
6733        __is >> __areas[__i];
6734    if (!__is.fail())
6735    {
6736        swap(__x.__p_.__b_, __b);
6737        swap(__x.__p_.__densities_, __densities);
6738        swap(__x.__p_.__areas_, __areas);
6739    }
6740    return __is;
6741}
6742
6743_LIBCPP_END_NAMESPACE_STD
6744
6745_LIBCPP_POP_MACROS
6746
6747#endif  // _LIBCPP_RANDOM
6748